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Issue. Been chasing it for a couple of months. Will not do it everytime, but if it takes 10-15 seconds of cranking to start (first start of the day) it will also result in a rough idle (idle up to 2000 rpm for 15-30 seconds before it smooths out as much as it can).
LH 2.4. Most recent work:
O2 sensor replaced about 3000 miles ago (failed)
Replaced all 4 spark plugs wires and coil wire (found 2 with no continuity)
R&R Distributor cap and rotor
IAC cleaned (looked okay and nothing was sticking)
Throttle body cleaned (didn't see anything out of the ordinary)
This helped some of the rough idle, but nothing was really fixed.
So today, I ran diagnostic control functions 1 through 3.
#1. Nothing but 1-1-1
#2. popped 2-3-2 (Fuel system compensation for rich or lean air/fuel mixture at Idle) and 2-3-1 (same as before except at cruise).
#3. Heard everything as it should be.
I then ran checks on the O2 sensor. Disconnected it was cycling between .25 and .98 volts for the first few minutes and then it settled down to around .35. When I would move the throttle it would start its dance again.
I listened to the injectors and could hear clicking in all four. I pulled the fuel rail as a whole and check for function. Good spray. No drips after turning it off.
Pulled the 4 spark plugs (NGK BPR6ES). Found that the gap had grown from .030 to about .038 on all 4 in 8000 miles. All plugs where "white" so lean is the condition. Regapped to .030
Really won't know for a few days, but looking at my Trusty Bentley manual, I notice that the same fuse that protects the heated seats (has been blown for several months) also protects the fuel injection system relay. Sooooooo, what do you folks think? Has that been the problem the whole time? I haven't figured out what that relay does yet. So new fuse goes in, disconnect the seat heater wiring and watch and wait.
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TPS NMI?
Sorry, I don't recognize those but I'm willing to do the diagnostics.
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translates to Throttle Position Sensor, (No Message Inside)
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850 / 240 / Mini
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...I notice that the same fuse that protects the heated seats (has been blown for several months) also protects the fuel injection system relay.
To which fuse do you refer?
The fuel system relay coil supply voltage comes from the 30A fuse in the underhood fuse block. The same fuse supplies the ECU and ICU.
The system relay supplies F4 and the main pump. F4 supplies the tank pump and the O2 heater. If F4 is the blown fuse, it can certainly be the problem; no tank pump running. But none of the schematics I have suggest that a seat heater is fused on the same circuit.
The seats are fused by F13.
Is it F4 that is blown or F13 or ???
BTW, in your report on things done I did not see anything that rules out intake leaks. Did you check for leaks from one end to the other?
--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)
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Finally had a moment to look at the Bentley wiring diagrams. I see now what your speaking of. Looks like they had a hot start relay on there in 1989 models, but since then, it's been nothing but heated seats. So we'll see how she behaves the next few days.
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F13 is the fuze and the only reference I have so far is the Bentley on page 033-2.
13 16A 1987- radiator fan relay, instruments, turn signals, seat belt warning, fuel injection system relay and heated seats. Of course, that could simplu be a list of all that has ever been on F13 so......
As far as intake leaks, we recently had to pull the head to address an oil leak, so she has all new gaskets all the way around and we did recheck the gaskets and double checked all vacuum lines.
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posted by
someone claiming to be dear1700
on
Sun Mar 29 16:28 CST 2009 [ RELATED]
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what about the intake hose from the AMM to throttle body?? Flame trap hoses sealed tightly?? (I've had the big one slide off before)
You could try cleaning the AMM with a special cleaner made by CRC. OOHhh..make sure the prepump is running, take off the gas cap, stick a hose down there and listen to it, you should hear a humming...no humming no pump running.
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All hoses checked out during the vacuum leak search along with the intake hose. Just for grins I R&R'd my backup AMM and no difference.
Performance wise after what we did yesterday, somethings did improve, but not enough to declare victory.
I'll try the hose idea to listen for the prepump. Can that have that much of an effect on fuel pressure to the injectors at idle?
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Hi there,
Can that have that much of an effect on fuel pressure to the injectors at idle?
Yes, actually. I think Jeff would agree: Rough idle fixed!!! Pre-pump was the culprit
For some background, you might have to click his "every post" link and look at the old threads, but it is an easy and worthwhile check. Run the tank pump only, by removing fuse #4, and connecting a jumper between fuse 6 and the right or inner terminal of #4 with the car off and key out. If it is quiet, you'll hear it from up there.
Regarding your fuse use, any discussion of fuses on a 93 needs to be based on late or early production that year. The late production is recognized by a large, obvious fuse box attached to the positive battery terminal. If you have one, you won't even have a fuse #6 inside listed on the panel label. Bentley's fuse list is too con-fuzing and mixes in cars marketed all over.
The problem you are having sounds much like Jeff's, and once you restore the fuel pressure, you'll need to reset the fuel trim adjustment the computer made, by removing and reinserting the fuel injection fuse - #6 on the early production 93.
--
Art Benstein near Baltimore
Nobody cares if you can't dance well. Just get up and dance.
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Art, as usual, you get an A+ for craftiness. I like the paper clip as a jumper!
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Paul NW Indiana '89 740 Turbo 140,000
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Art,
Thank you for taking the time to revisit this from the other posting. I will give the prepump a check tomorrow. Hopefully "good" news. Although I think I will be adding a new tool to the tool chest. However, I did like the picture of the gear puller, open end, etc. I might give it a try.
Cheers,
J.R.
Southern Maryland
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That puller just happened to fit. The idea is more like try scrounging around the house for something that might work as a spanner before resorting to buying what might be a one-use tool. Some have implemented some kind of drain-fixing tool or basin wrench of some sort as a spanner for the bung nut.
On the other hand, getting a new tool has a certain pleasure factor.
--
Art Benstein near Baltimore
Since it's the early worm that gets eaten by the bird, sleep late.
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Well....might not have to buy the tool.
I did as you suggested and we could hear the prepump just fine. So the next step is to check the current draw. Could be a clogged filter sock or a break in the fuel line between the prepump and hardline.
Any other thoughts?
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You could check the draw, but I don't know what you'll learn from it. I've never seen a clogged sock, so I can't tell you how that would affect it, but I can tell you the tank pump gets worn brushes. When the brushes wear short, the commutator may stop on a spot where they don't make contact. Then the only thing that will get the pump moving again is a bump, or other mechanical influence, not electricity.
So, when I test the tank pump by listening for it, I make and break the connection a dozen times or more, daring it to not start up. Like playing with Vanna and the wheel - you spin until it comes up bankrupt.
Also, I've not yet seen a split hose on the newer 240's that use the molded hose to connect pump and sender. Just my own experience though. I'd tell you if someone else had posted a picture.
--
Art Benstein near Baltimore
If at first you don't succeed, skydiving is not for you.
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Darn it. I kept trying to get Vanna to spin the wheel but no dice. Must have tried to trick it 2 dozen times and the little pump fired up every time looking for tht dead spot. So I ran some load tests:
- engine off, pull #4 fuze, short across #4 fuze to #6 . Load starts out at 4.9 amps and drops to 2.8 amps in about 30 seconds. Tested #6 with no fuze and the preload from the ECU(?) was about .01 amp.
- go to the trunk, set up a load test and with the engine running the load ends up at 1.2 amps. Bentley sez it should be 3-4 amps.
So to your point, not sure what that tells me. If the pump were worn, then it would operate at a lower load? Car's got 150,000 miles. Probably due irregardless? Thoughts?
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That tank pump lifts fuel if it runs. The only wear it will encounter is the brushes, which would cause the wheel to turn up bankrupt, so I think you can discount the tank pump as a cause. To explain the numbers you got across 4, the fuse supplies both the tank pump and the oxygen sensor's heating element. The numbers you got across 6, if your 93 is early production, just indicate the memory keep-alive current. The main pump current would be measured between left tab of 6 to left tab of 4 with 4's fuse removed. It isn't a fair reading, because it is based on no feed from the tank pump, but in order to get that reading independently, you'd have to run an additional jumper from left side of 6 to right side of 4. Confused?
Anyhow, I don't believe it is pump related after the results you bring back. Going back to your original post, the hard starting is accompanied by flooding symptoms, but intermittently, the car starts normally. Only a thought, but could it be missing a spark during cranking some of the time, as would happen when the crank position sensor (CPS) is borderline?
It reminds me of a similar bout I had with an 89, after replacing the CPS just because the old one was a yellow-band cable and cracked. The hard starting was accompanied by occasional starter kick-back, which I later found to be spurious ignition on the compression stroke. A second CPS set things right, but it was a tough one to prove, and cost me one destroyed starter.
However, an intermittent CPS could just result in intermittent spark and not necessarily the symptoms I had.
--
Art Benstein near Baltimore
A backward poet writes inverse.
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Thanks Art!
Now the load numbers make sense.
What's your experience tell you about the life of a tank pump?
Any brand of CPS better than another?
Intermittent hit again today. We went through a series of starts and restarts and 4 times in a row it started just fine. 5th time it took 15-20 seconds of cranking before it started to try and fire.
I replaced the factory CPS 5 years ago at 90K miles with similar symptoms before it finally failed. I will check it out. Is 60k on a CPS typical?
I'll go through as many steps of AllData as I can. But it's a $30 part so I don't know how much I'll monkey with it. It's a bear to change out. Time to teach my son how to do this one!
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- I have cleaned every ground including the ground from the battery to the block.
- I have checked all vacuum lines and have found 2 with small leaks and will address. The only line that I have not checked yet is the brake vac.
- changed out the 5 year old CPS but not change.
- I checked fuel pressure by dismounting the fuel rail and lifting it away from the intake manifold, screwed on a shrader valve fuel pressure gauge, shorted the fuel pump. +40 psi, manipulating the fuel pressure regulator with vacuum caused a reduction in pressure and when I pinched the return line I saw a significant spike headed for 100 psi. The pump is only 3 years old.
- Engine vacuum at idle is 18.
- I posted a separate thread on the ECU harness checks #24 and ground for the O2 sensor. I did not get continuity.
For grins I swapped in my spare 4 year old known good Programma 561 (951) ECU. I'll try it for and see what happens. Is Programma any good as an aftermarket ECU?
Any other ideas?
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