Our 1987 240 GL with 225k this spring lost power and I took a quick look and found that the first 2 cylinders had about 150 psi and the 3 and 4 had 0! My feeling was that it at least needed a new head gasket. I started the project a couple of weeks ago and indeed it needed a new head gasket. I also had the head milled and new valve seals installed. The valves all looked good. Got everything back together and noticed that the engine was not running smoothly and stalled frequency after accelerating… Did another compression test when engine was warm and all cylinders are 155 psi… All spark plugs looked clean and dry. I started to pull the each spark plug wire and found number 2 did not make a difference to the engine running all others caused the engine to run much rougher… Check spark, changed out wire, distributor cap, and plug but no difference… I did spray starter fluid around the base of each of the injectors and the engine performance did not change…
From here I am thinking the # 2 is not getting any fuel! I am not sure how to test if the injector is getting power or if the injector is working correctly. Is there anything else I should be looking at before taking apart the fuel system?
Roger

Good news! She runs smoothly.. Just stalls once in a while when decelerating... This seems to have happened before the head gasket!
Just to recap.. It seems that both #2 and #3 injectors were not firing due to the wires inside the connectors had backed out. This was found by the test to listen to each injector using a long screw driver. I took all the connectors apart and reseated the wires in the connectors.
Thanks
Roger

That's good news. The stalling when decelerating may just be a matter of cleaning the throttle body and idle control valve, unless you already did that as part of the head gasket repair.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (fixed the ignition - now back to the brakes again)

After thinking all day about this… I looked at the three ground wires that I attached after cleaning the lugs.. Two are attached to the fuel rail and one is attached to a bracket holding the throttle cables. I do not see any other wires just hanging.. With flashlight in hand I looked closely at the injector connectors and found that both number 2 and 3 connectors had the wire lugs out of the connector.. I am thinking this is a big problem! Seeing the connector is keyed I am assuming the wires need to be put back into the connector it the correct location. The two wires are yellow/red and white/green. Is there a polarity for the two wires? Reading I have not found any info on this. I have the wire holder of the connector facing down the yellow/red wire one the left side.. Just not sure if this is correct???
Your suggestions have given me ideas and hopefully I have formulated a logical approach to resolve this issue!

Look at how the properly-functioning injectors are wired. The wire colors/positions should be the same on all four injectors. Check out page 13 on this document:

http://www.volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/TP31054-1%201987%20240%20Wiring%20Diagrams.pdf

Note, by the way they're wired, it appears they're gang-fired (all four injectors firing simultaneously).

Thanks to all for your suggestions… I tried to be very careful about aligning the 3 timing marks when I was installing the timing belt.. So I am hoping not to have to revisit checking the timing belt install.. I had a couple of minutes and tried:
1. First switching injector wires 2 and 3 and the engine would not start.. Switch them back and it started..
2. Then I put a screwdriver to the injector body and heard a clicking on #1 & #4 nothing on #2 and #3.. I did the same test on another 240 and I heard the clicking on all injectors..

3. I again removed one spark plug wire at a time and engine did not start with #1 and #4 wires removed. With #2 and #3 it started and ran as rough.

That is all the time I had this morning…

If it was simply a problem with the T-belt being out of time, it would affect all cylinders equally.

Also, traditional thinking is that injector timing is not particularly critical. If it was, then how does an engine run when they fire in pairs (or in 3's in the case of a six cylinder)? The cylinders certainly don't ignite in pairs or in 3's. In fact I believe that on some engines ALL injectors fire in unison.

As was suggested, testing for signal at the connectors, either with a noid light or maybe an analog volt meter, sounds like a good idea about now. You may want to test for wire continuity between the connector and the ECU. Any chance you didn't get all the grounded wires reconnected when you reassembled the engine?

Hang in there.....
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)

if you have strong reason to suspect 3 injectors work and 1 does not simply swap positions of the injectors. place a known good one into the cylinder position of the bad one and let the bad one go where you know the cylinder has been firing.

you'll know fast one way or the other,

Hello interesting problem you have there with trying to "see" what's happen.

I have time to kill tonight I can share some worthless thoughts with
ya!
I might suggest a "noid light" that plugs in between the connector and the injector.
I picked up a set that covers different cars, for only a few bucks and used them once to find a corroded clip.


On the cars the injectors fire all the time with a varying pluse width. Its my understanding they are wired in pairs but do not work sequentially.
I do not know if you can actually put them on wrong but if you could it might be that cylinders two and three could be crossed. One from each separate pair. If they are fired differently as a set, that might cause a problem. The firing order for spark is 1,4,3,2 ... I think? 4&3 might be divided.
Probably a real long shot for it to be so!

You have received three different posts each with angles of attack that seems to me should isolate the problem. The last one requires doing what you suggested doing and that's tearing into the fuel system. That could be some work for you, if you do not have all the goodies, he has put together.

The screwdriver or a mechcanic stethoscope even works easier.
If you use one of those scopes, hook up to the ears, it's amazing how the injectors sound a lot like a jack hammer but with a bit of ringing noise in there. It's a treat to listen too! Make you wonder how they can last so long.

I also have this thought. If you have one of those infrared thermometers, you might be able to confirmed the that one outlets of the exhaust manifold could be cooler that the others? It would have to be more than fifty degrees to be suspicious.
Again just a thought.

There is a part in your story I'm undecided about.
This is why it stalls frequently after an acceleration?

This worries me that you have an air leak behind the AMM somewhere?
You might want to check the accordion hose carefully.
It could be that the number three cylinder is just running very lean.

Another thing I would like to ask.
Since you had a valve seat or seats replaced, did you also do the valve guides?

I see you replaced guide seals and I just wondered if you might have one cylinder with a sticking valve.
The new or the old guide has less oil now.
It's After it gets hot or after a hard acceleration. You do not say if it becomes low on power or having a definite miss but it does do the stall thing? This all seems twisted as well, but I am busy (:)

I will ponder for a moment that it might be only an intake valve or better an intake gasket an issue?
Since, you shave the head for warpage....
Did you run a straight edge over the four joints of the intake manifold?

They can become very uneven or twisted over time.
Especially if there was some stress in the casting back when it was made. The repetitive heating over the years, may have released it and unbolting it let it go wang!

The possibility is, that the new gasket cannot not fill a gap someplace.

Thanks for reading anyways!

Post back what you find!

Phil

Just so there's no confusion -- machine man wrote--"The firing order for spark is 1,4,3,2" -- I'm sure he knows better and what he wrote was either a typo or due to too late a thinking session -- correct firing order for most inline 4 cylinders (very early Toyotas being an exception) is 1-3-4-2. -- Dave

Hi Dave!

Thanks for saving my buns there!

Yes it was late as I was trying to wind myself down to go to bed.
I surprised in did not throw a "5" in there for good measure.

It goes to show you that things can get crossed up despite good intentions!

I have been a good example ... for years! (:-)

Phil

If you think it might be an injector or associated wiring, you could try pulling out all of the injectors, reconnect the fuel rail and wires, and let each injector spray into a small container while you crank the engine over. You should see equal amounts of fuel spray into each container. You can swap the suspect injector with another one to see if the problem follows it.

Since all cylinders now show compression readings about equal to your previous best, the timing belt is correctly indexed. If the No.2 cylinder is getting spark, then it almost has to be a fuel injector that is not injecting. Put the tip of a long handled screwdriver onto the metal body of the injector while the engine is idling, and your ear to the plastic handle end - there should be audible clicking noises as it operates. Compare to one or two others.

If it has the same clicking noises as the functioning injectors, it's probably plugged. Not that likely.

If it has no clicking noises there is an interruption in the electrical circuit. (More likely) Remove the connector, check wiring for breaks, inspect for bent/broken/corroded contacts in both connector and injector and reinstall. Detach and reinstall a couple of times to wipe the contacts free of corrosion.

Let us know how that goes.
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Bob: Son's XC70, my 83 244DL, 89 745 (Chev LT-1 V8), 98 S90 (recently sold) and 2010 XC60. Also '77 MGB and four old motorcycles

I would double check everything related to the timing belt install, it may be one tooth off.
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Bruce S. near D.C.