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It seems that the more things I "fix" on this car, the worse it runs. Since the most recent work (described below) the car has run very poorly, with rough idle and poor or nonexistent acceleration from a stop.
Is this system designed to open injectors 1-3-5 or 2-4-6 as a group? With the cold start valve disconnected, it seems that only injectors 2-4-6 are working:
- The car starts and runs (poorly) with injectors 2-4-6 connected and 1-3-5 disconnected. Disconnecting 1-3-5 has no effect on idle or performance.
- The car will not start or run when 1-3-5 are connected and 2-4-6 are disconnected.
- Disconnecting any one of 2-4-6 causes the running engine to stop.
- When working the throttle, the throttle position switch causes injectors 2-4-6 to "click" but injectors 1-3-5 remain silent (is this normal?).
- Connecting the wire for injector 2 to inj. 3 results in "clicking" from inj. 3
when working the throttle.
Is it possible that there is some problem in the wiring (insulation on which is dried out and failing) or circuit that would cause this? Am I in for a new ECU? Does anyone know where I might find one for a reasonable investment?
More info:
I recently replaced the distributor, replaced the engine temp sensor (and repaired the wiring which had become shorted), and inspected the auxiliary air valve and found it to be working. I measured the fuel pump pressure to be 30 psi. I measured the resistance for each of the injectors at 2.5 ohm.
Following this, the car was running rich and would not start when warm unless the accelerator was pressed to the floor. I suspected the cold start valve was leaking or on all of the time, and confirmed this when I found a pool of gasoline in the intake manifold under the throttle body. So I disconnected both the fuel line and the electrical connection on the cold start valve.
Concerned that I may have a vacuum leak somewhere, I also disconnected the vacuum to the dashboard systems.
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Just want to follow up and give the final status of this mess for future reference.
I spent many hours chasing down possible problems. It was a real headache because there were multiple issues causing problems at the same time. The things that really got me turned around were that a new distributor was not working properly and that it and throttle position sensor were both failing to send signals to injectors 1-3-5 (unusual coincidence). Also, the fuel issues were compounded by an intermittent problem with the spark. My lengthy troubleshooting and repair process is described here.
I removed the ECU and made sure that the right resistances or signals were being received at that point through the wiring harness. Check.
I found that a wire from the distributor to the electronic ignition module was shorting intermittently. When this shorted there was no spark. I made various attempts to get it working and thought I had it fixed.
I found a junk yard only 2 hours away (neighbors by Montana standards) that has an impressive collection of Volvos, including 164s. I visited and found an ECU there and bought it. I also searched for a replacement ignition system wire without success. This particular coaxial cable seems to be unique to 75 models.
I installed the "new" ECU in the car and it seemed to be running well with a reasonable idle. I went inside to get a few tools but by the time I got back outside the car choked, lurched, and died. It would not restart.
I pulled the distributor and in the process the suspect ignition wire broke entirely. I bought appropriate electrical quick-connects and re-engineered/replaced the ignition wire so that it made the connections and did not short.
I reinstalled the distributor and the car had spark but idled very poorly. I was back to the starting point...no fuel injection at injectors 1-3-5!
Given that this was now happening with two different ECUs, it had to be somewhere else. Turned out it was the new (rebuilt) distributor! My assumption that the contact points sending signal from the distributor to the ecu were working turned out to be wrong. This contact system on the one side would work intermittently, and briefly, but not regularly. I returned the distributor for a replacement, tested and installed the replacement, and everything seems pretty good now. The original ECU is back in the car.
The throttle position sensor still only fires injectors 2-4-6 when the throttle is pressed. That must be in the TPS and I will see if I can work that out.
I have a few vacuum leaks to take care of. I will install new o-rings on the injectors this weekend (spraying around injectors 3 and 4 with starting fluid causes noticeable changes in idle), and will also install new plugs. I can hear a vacuum leak at the point where vacuum is attached to the brake booster, which needs to be addressed.
Thanks to everyone for their helpful and useful suggestions. I hope my experience may be of use to others.
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Remember to rotate the engine to get the odd numberd injectors to click. If the distributer is pointing to the even numbers, that is all you get.
Replace the starter injector after you get everything else done.
Side note: my 1975 164 lost an intake valve spring on rocker #1. It flooded after a few seconds of running. It took me months to figure out that one! I was so tired of pulling the spark plugs!!
I also sent the injectors to http://www.cruzinperformance.com/ and was told 4 of the injectors were totally worn out. Cleaning cost about $15 each.
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Very interesting...so when the engine is not running you get additional pulses on one set but not the other. I've tried this throttle test several times during this process and always see 2-4-6 but not 1-2-3. It is like flipping a coin 10 times and getting heads every time.
Yes, I hope to replace the cold start valve at some point. But for right now it is out of the system electrically and physically.
Based on your recommendation what I may do is purchase a couple of rebuilt injectors and send a couple at a time to be inspected and cleaned.
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Not like getting heads 10 times in a row. Engines almost always stop in the same position when shut off.
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Check the ground wires for the injectors that are mounted on the intake manifold.
If the grounds are okay you may have a problem with the contact trigger points in the distributor or with wiring/connections associated with the contact trigger points.
FYI, the throttle switch does not affect which bank of injectors are firing. The computer sends the signal to each injector based on what the contact trigger points are doing.
Is it possible the wires at the contact trigger points are not connected correctly after your repair?
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
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Oh, yes, I should have mentioned that I did check all the ground connections. On this car they are actually around front under the battery (a particularly bad choice in my mind since they can easily get corroded there). I also checked the resistance of each injector at the ECU wiring end to be sure that they were properly wired and grounded.
I think that I have the contact trigger points working and connected properly with the second replacement distributor. But that certainly was the problem for more time than I care to admit...I wasted a lot of time and effort while I assumed that a newly rebuilt distributor was working.
What the throttle switch does do on my car is to send a series of pulses to the injectors when you open the throttle. If you turn the key on, but do not start the engine, you can hear a series of "clicks" every time you open the throttle. Every time I have done this I get a series of pulses on injectors 2-4-6 only.
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The injector ground point I mentioned is for the 4 cylinder, I forgot you had a 6 cylinder.
The contact trigger points in the distributor is comprised of a pair of points just like the ignition points that trigger the ignition coil on non-electronic ignitions, but they only send a ground signal to the computer that the computer uses to determine when and how long to fire each bank of injectors.
1 of the points sets in the contact trigger points works the even numbered cylinders, while the other is for the odd numbered cylinders and only 1 bank of injectors will squirt at time. If you want to check the opposite bank, turn the engine or the distributor. And unlike ignition points, the trigger points aren't supposed to be adjusted.
You may need to clean the trigger points and that is a routine part of 1 of our tune ups on D-jet equipped cars. The trigger points can get oil or points grease on the contact areas of the points. There should not be any pitting because only a ground is passed, no voltage, so you should not use a file or sandpaper as it can change the timing for the computer.
FYI, you should use a proper points grease on the rubbing blocks of the trigger points and on the lobes inside the distributor for the trigger points after you have cleaned them being careful not to get any on the contact areas of the points.
Even after cleaning we have found some trigger points can still be defective and needed to be replaced.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
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1st I;d pull the distributor & make sure both D-Jet points are good.(One fires one group of 3 cylinders)
- When working the throttle, the throttle position switch causes injectors 2-4-6 to "click" but injectors 1-3-5 remain silent (is this normal?).
Not normal, the 6 squirt as a group when supplied by the throttle switch. Your description makes me believe the under seat Control Unit is cooked on 1 side. At best, it's the wiring harness, pull it & run an ohm meter over it.
--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.
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Good advice...resistance and function measurements for the wiring harness, sensors, injectors and triggering system are on the agenda for the weekend!
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There are two sets of trigger points in the lower part of the distributor. When each set of points opens and closes it triggers three injectors. So if you have three injectors that work and three that don't, it is a near certainty that the problem is with one of the two trigger points. A common problem is that the fenolic (sp?) cam followers on the trigger points (just like ignition points) wear down until the points no longer open. The stationary half of each set of points can usually be tweaked with needle nose pliars such that the contacts will once again open as they should.
If you look down low on the distributor, you will find where a 3-wire connector attaches to the trigger points. The center pin is common to both contacts, so you want to check for continuity first between the center pin and one side pin, then the center pin and the other side pin. Trigger point timing is not at all critical - as long as they do open and close. I always shot for about 180 degress of open and 180 of closed. (That's 180 degrees of distributor rotation which equals 360 degrees crankshaft rotation.) Anywhere in the ballpark is good.
I always found it easier to pull the distributor out and do all this on the work bench.
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Thanks, Chris. Having just replaced the distributor with a rebuilt unit, I have been working on the assumption that the triggering mechanism is working...but I should of course never assume anything. I'll check it out. I should also check that the wiring between the distributor and the ECU is ok, I guess.
I don't think a faulty distributor triggering system would explain injectors 1-3-5 failing to click with the throttle valve switch, unless they are not programmed to do so. Does this sound right to you?
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They should click with the throttle position switch regardless of whether the trigger points are working or not. I would double check the grounds for those injectors -- are there two separate eyelets on the manifold with three wires each?
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I'm not sure where they are grounded...I will spend some time and see what I can find out. But faulty ground, if the two sets of injectors have separate grounds, could very well be the problem. Thanks.
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They are grounded on the battery box & are often rusty.
B20 was neater/better on the intake.
--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.
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Failing to fire while cranking or running, certainly sounds like a bad set of trigger points.
But not firing when you open the throttle switch, points to some other sort of problem.
No experience with B30 D-Jet, just B20, but they're very similar. And a B20 D-Jet would certainly fire both sets of injectors, back and forth, as the throttle was opened.
Wiring or the ECU is starting to look likely at this point.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)
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Thanks, that's very useful information. I've got to spend some time tracing the wiring and connections. Would be great to find a wiring problem somewhere...because ECUs are hard to come by.
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If you look at the throttle switch carefully, you'll see this:
1) An idle switch (activates the special hand tuned idle mixture circuit, really, this hand tuned idle mixture was the entire reason D-Jet was used, made the idle clean enough to pass the early 70's emissions tests)
2) A switch that closes as the throttle opens (via friction), it opens as the throttle closes
3) Once that is closed, it slides across an alternating 'sawtoothed' set of contacts. Two circuits, one for each of the two injector batches. As the contact slides across, it's basically adding an extra firing cycle, the same thing the distributor contacts do.
So basically, as you put your foot down, you just add in fake 'engine rotation' signals, fires the injectors more, acts as a fairly low tech acceleration enrichment mechanism.
If the injectors aren't firing when the engine is running, and they're not firing when the throttle is opened, that (within the realm of reasonable probability, i.e. simultaneous unrelated failures) eliminates the distributor contacts, and the wiring to them, as suspects.
It likely means that the ECU is receiving signals to fire that batch of cylinders, and is either unable to send the signal (internal failure*) or the signal isn't getting there.
Later model injection systems generally have the car supply 12v+ to one side of the injectors, and the ECU grounds the other side of the circuit to open them, but D-Jet does it the opposite way. The ECU sends out switched current from the ECU (not 12V, I think it's 5V, or less) to one side of the injector, the other side is permanently grounded. On the 4 cylinder B20E - each injector has it's own individual wire from the ECU, even though they're fired in batches of 2. And all ground wires are grounded at the same point (on the manifold).
Here's a 164 injection wiring diagram:
http://www.164club.se/service/el75.jpg
Looking at that you can see how almost comically clumsily they modified the 4 cylinder ECU to handle 6 cylinders. Along the top edge of the picture, just left of center, around the larger '81', is the injector wiring. You can see that the ECU still has 4 outputs (2 batches). However, two of the wires (#4 and #6) go to single injectors, as in the B20 installation. The other two outputs (#3 and #5) each fire TWO injectors, via a split in the wiring.
Now, that wiring diagram also shows all 6 injector grounds going to a common source. Without really looking at the wiring loom itself it's hard to say if all the wires are really spliced into one before the ground eyelet which is bolted to the manifold or not.
But, just from looking at that wiring diagram, the whole wiring aspect is starting to look a little dim. I don't think a wiring fault could produce the symptoms described.
1) Since the distributor triggers and throttle switch triggers both fail to fire that batch of injectors, it's unlikely to be a wiring or trigger switch issue
2) The hard wiring scheme doesn't seem to support any way in which 3 cylinders in a single batch could be incapacitated. 2 of them, but not 3. There's a faint possibility that they're also grounded in the same grouping as the batches, but there's certainly no reason for them to have wired them that way.
It really does seem to leave it up to an ECU problem, where it just isn't firing one of the batches because of an internal fault.
They really are large scale, non integrated circuit, analog electronics though. There are probably people about who know how to fix them. And probably people who haven't really ever seen a D-Jet computer, but who know electronics well, and could have a good chance of cracking the case open and finding what resistor/capacitor/transistor failed, and replacing it.
Although a cheaper bet is still probably just finding another 164 ECU. They're rare as can be, but they also seem to rarely fail, so it's a case of low supply teamed with low demand - they're not likely to be ridiculously expensive.
And worst case scenario? Replace that cake pan ECU with a programmable Megasquirt ECU! That has certain other benefits.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)
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Thanks for the insightful and complete analysis. I was studying the wiring diagram myself and was surprised to see that they had stuck with four injector connections and just run two injectors of a couple of them...clumsy is a good description. I will have some time to really get in there and go through the wiring carefully this weekend...but I am in agreement with you that I am likely looking at an ECU problem. I haven't seen or found a circuit diagram for the ECU...which would be rather helpful in trying to diagnose what might be the matter in there. Thanks again for your help and analysis.
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FWIW there is a B30 D-Jet computer on eBay right now. For $499 BIN.
Which is a bit steep.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)
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I saw that. I think it is time for me to make on offer on it.
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I think Walrus said he has one?
I have a few, but they are in .au. I have no clue how to post it.
--
Three 164's, Two 144's, One 142 & a partridge in a pear tree.
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here's a link to the volvo djet manual-
http://volvo1800pictures.com/document/fuel_injection_fault_tracer/fuel_injection_fault_tracing.pdf
good luck, chuck.
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That manual really opened my eyes on diagnosing D-jet issues. You've got a K-Jet, but I think it covers that type as well.
The book is absolute gold.
Definitely check out K-jet.org
http://www.k-jet.org
Lots more information - including greenbooks!
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He has a D-jet! NO 164s came with K=jet! They even had an electronic distributor
with D-jet triggering points for the 1975 year model.
--
George Downs Bartlesville, Oklahoma
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a 1974 with d-jet? that's peculiar.
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Obviously you have not worked on a 74 or 75 164. With the exception of a VERY few
carbureted ones for backward countries, all the later 164s came with D-jet.
No 164s were factory equipped with K-jet.
--
George Downs Bartlesville, Oklahoma
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164s are a bit out of my experience, but a 1975 240 is K-jet. I thought that the 1974 140s were also K-jet.
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The 1974 140s were indeed K-jet.
But the 164 is different.
--
George Downs Bartlesville, Oklahoma
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Point taken. I'll just sit on my hands now...
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164s are a bit out of my experience, but a 1975 240 is K-jet. I thought that the 1974 140s were also K-jet.
They were... but as George stated, not the 164's.
--
Gary L - 142E ITB race car, 73 1800ES
BlueBrick Racing Website
YouTube Racing Videos
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Thanks, Chuck. Looks like a very useful manual written by someone with a good sense of humor. Might be just what I need!
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Brother,
I can relate. Don't rule out a bad fuel pump or clogged fuel line. Always check the fuel pressure first. The get creative and disconnect the fuel line under the hood and and fuel filter. Then blow the line back. You'd be surprised how much junk may get in there. If the pressure is good and the line if clear and it still runs poorly, then head over here:
http://www.rockauto.com/catalog/moreinfo.php?pk=482039&cc=1286951
Get a whole set and replace the entire line. If it is running rich, then more than likely it is a bad injector or two. This will take time to do, but I have done it just recently and I am a shade tree mechanic at best, so if I can do it, you can too.
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I have replaced the fuel filter recently...and the old one was certainly full of plenty of junk.
But yesterday I measured the fuel pressure to be a constant 30 psi (at least at idle), so I think that is not likely the problem.
I hesitate to buy and replace the injectors just yet, because it seems that the bigger issue at the moment is that the circuit/ECU is not sending an electrical signal to injectors 1-3-5. It is good to see relatively affordable rebuilt injectors are available, though.
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