To all those experts, I'm in need of help. My 1987 740 turbo, LH-Jetronic 2.2, will not start. I've got spark at the #1 spark plug, fuel coming out the fuel rail with #11 fuse (in-tank pump) pulled, and I've got 12 VDC between the green wire lead of #1 fuel injector and battery ground. I've just recently replaced my wiring harness with one from Dave Barton. The old wiring harness had "disappearing" insulation at the Idle Air Control Valve leads and the H battery ground wires were bare. That said, it appears that the ECU is properly grounded through ECU #5. I've tried different ECUs from eBay and the local junkyard (3 of them, in fact), but to no avail. Just today, I replaced the Power Stage with one from the junkyard. That did not work. I'm thinking now that it could be the ignition control unit (ICU). I'm running out of ideas. Any ideas? Thanks.
Oh, I forgot. The camshaft rotates on Ignition START, indicating an intact timing belt.

 

If you have spark, then I wouldn't suspect the ICU. Instead, I would be looking at the fuel side of things. I would be checking the fuel side of things. Have you checked the pressure at the rail?

 

I like to shoot some starting fluid in the intake to separate the "fuel vs. spark" issue. Many times "have spark" may be misleading...
Have you looked at the Hall sensor and its wiring? Often it's a problem on these cars.

 

Okay let me pick a part all your testing methods.
1: You need to check for spark at the coil
2: Saying you have fuel at the rail means nothing. Need an actual pressure reading
3:Okay you have power to injectors, but what about control?
4: Okay the cpu needs good grounds, but getting ahead of yourself,
5:ICU fine if you have spark
6: timing can still be off.
7: compression?

I'm not satisfied with your testing, you need start from scratch and test and provide use with test data.

 

Thanks, guys. I didn't think about the fuel pressure. Where can I get a pressure gauge and what are the specs? As for the Hall sensor, I replaced that a few years ago. If you get spark, doesn't that mean the Hall sensor works?

 

well the adapter for volvo fuel rails are goofy. you have to get a master fuel pressure kit.

HF sells one. I wouldnt trust it. OTC, mac, matco, snap on, cornwell. all trust names.

Yes, you are correct. If you have spark you have a working crank sensor. Considering there's 2 computers, the fuel computer may not be getting the input.... possible.

 

Pull the vacuum hose off of the fuel pressure regulator. If gas comes out, then you know that the regulator is off.

Another test that I would do is check the timing. With cylinder 1 at TDC, pop the cap off the distributer. The rotor should point to a line on the distributer base (or 180 from the line). If it doesn't, then your timing belt has most likely slipped.

 

??????
a leaking regulator, yes.
Usually don't cause no starts. Now if pressure was way to high or low via the regulator, didn't scenario.

 

that leaking regulator is going to flood the intake manifold with gas.

 

while it's running.

 

as soon as you crank it over, and the fuel pump starts, that gusher of fuel through the vacuum hose starts, PLUS the fuel pressure will be close to zero with a failed FPR bleeding gas out the vacuum port.

 

Never seen a bad FPR cause a no start... In theory may be, not in practice. I guess if the FPR was, well, missing, gas pressure would be affected...

 

Every leaking FPR I've seen isn't "gushing" out.

 

Guys,

Thanks for all the feedback. I'm not in a hurry here, so if you don't hear from me, don't worry. I'm more of a bicyclist now, and occasionally do Volvo work: basic maintenance on my wife's 940 and no-start work on my 740. If and when I get the 740 working, I'll post as to the cause, etc. I'm starting from scratch and redoing all tests.

 

If you where a mechanic in a shop; you would only have one hour to figure it out why your car isn't starting.

 

Finally got it started. A bit of testing here and a bit testing there over the months. My next series of tests (after previous post) indicated a faulty Hall sensor. No EM2 (2nd switch in fuel pump relay) closing at ignition Start (see my no-start manual at stepbystepvolvo.com). So, I pounded in a new Hall sender in a spare distributor I had. I took out the suspect distributor today and ran a "Hall" test on it and got spark! (The test: roll back rubber boot of high tension wire and place 1/8" from bare metal--strut tower is convenient, distributor out of engine and in hand, Hall wire plugged into Hall plug of distributor, ignition ON, rotate distributor shaft. If fine, you should get spark out of the high tension wire; if faulty, no spark.) So, I put everything together again and cranked it. And the engine started. This has been bizarre, to say the least. The test results varied from one test to the next. I believe it was the spirit of our former dog, whom I promised to keep alive if he had a good appetite. In the end, we put him down because he could no longer stand on his own because of old age, though he could still eat. A broken promise! Could he be getting back at me? Other things have happened too, like nail in my wife's 940 tire, microwave broken, hell of a time installing a new waterpump on my wife's 940, etc. Go figure. Can't say that I can trust this car anymore though.

 

Hey dude. pretty god damned sure I know exactly what the problem is and it was never the impulse sender. So hear me out.


Go to your ICU (the ignition box) and pull the harness connector.

grab like a pick tool or something like a scribe or just something with a very small long tip like the tiny screw drivers you could use for laptop repair.

Inside that harness connector, are little metal tubes. On the sides of those little tubes are little prongs.

Those little prongs get bent back away from connecting with the posts on the ICU.

Causing this exact (drive you nuts) issue.

Bend those little bastards back in to the tube so they will contact with the ICU posts solidly again. Be super careful and gentle though, (use a pair of optivisors if you have to.) that you don't bend them wrong or too far as they will get pushed down into the tube when you reinsert the plug.

You only want them bent back in enough to make contact.

You'll see what I'm talking about when you look super closely at the connector.

If you do this correctly. You will be amazed.

 

the connector you describe with the tubular pins sounds like the chrysler ICU on the LH2.2 240's. The 740 used a different ICU, different connector. not quite sure what, I've not had a lh2.2 740 (my 92 is lh2.4 and has an ezk116)

 

jupo, you may be right. I futzed with the ICU pin connectors many, many moons ago. Back to no-start again today. I will look at the ICU in the near future.

 

Well, after 10 months of no-start, I finally got consistent test results. Got motion of the rocker arms, got spark, but no fuel delivery. (When the fault first occurred, I got motion of rocker arms, got spark, and got fuel delivery.) Turned out to be the fuel pump relay. Replaced that, and the engine started. But, now I have a noise coming from the ECU. I will be posting a new thread for that problem. (Don't know if I can upload a video clip.)

Thanks, guys.