I have a dvd with all 940 diagrams, but not 740. sadly, these dvds are very copy protected so its really hard to extract. also, they don't show the harnesses, they show the connections of the subsystems (one page for fuel injection on a turb, another for injection on a non-turb, one for ignition, one for headlights, etc etc etc (about 150 pages for each year).

 

Ah crap... thanks for checking tho. We've decided to try and patch up the original harness now that it's out of the car. It's a lot easier cleaning it up and wrapping it with 4 hands at work. It's looking pretty shabby.. and to think a local dedicated Volvo "specialist" garage worked on it last... Perhaps that was why it was so cheap too... The previous owner must have been lying .. as usual...

Hopefully there is no more buggery hidden elsewhere in the wiring.. It drove fine home, so it's got to be the wiring. Were talking multiple rubbing wires inside the black casing material here.. I found a website listing Volvo part numbers and applications for each one.. seems this particular harness is 87 740 turbo and 88 turbo 740/780 only... 1363217-1

found here;

Dave's Volvo Engine Wire Harness Page
They offer a good used one for 300 something... I'll try to fix mine first.

Hope this fixes it.

The other scariness was at the ignition control module plug... yikes..

Fingers crossed.

Cheers,
Mike

 

Hi, a bit of an update. We decided to fix up the old harness instead of buying a good used one. Upon complete removal of the old covering and previous tape patches, we found entire runs of exposed and touching wires. The coil wire was exposed a good foot or so and the injector wires from the resistor stack were at least 75% exposed and touching each other thru most of the harness. I think the weak coil output may have been caused by the bad coil wire and the injectors must have been batch firing continuously as all those wires were
Touching as well. We have about 80% of the job done, and hopefully be done tonite. So hard to believe it was so completely rotted inside the harness like that. This gotta fix something... I can't believe it ran as well as it did on the 35 mile trip home.

I'll post the results.

Cheers,
Mike

 

ok.. the wiring harness was completely gone over and every last section of missing insulation was taken care of. The harness was reinstalled and the alt and battery lines reattached....

Tried to start it.....


NOTHING....

SOS.... cranks to the moon and does not even try to run...

However, the plug wire was pulled and checked for spark... BIG spark now, looks good. So... we got gas... [can smell it cranking..], a big nasty spark..

and no start...

So far, the hall pick up was replaced, in tank fuel pump, a new fuel filter and the harness was fixed up... new cap and rotor... What is left now? How can it not run with gas and spark!?

Is it possible the timing belt jumped? I'm grabbing at straws now..

Any ideas before it gets hauled to the garage where a real mechanic can fix it?

I'm about to give up.

Any more ideas would be appreciated,
Thanks,
Mike

 

Well, are the plugs wet after a bit of cranking? If you got too much gas, pull all the plugs and let it dry out for a while. Then try again.

I'd also make sure the everything is plugged in correctly. The knock sensor and temp sensor can get reversed and plugged into the wrong sensors. Good spark means that the hall effect sensor is plugged in.

That's all I got.

 

Hi tj, thx for the idea. I have a spare set I can throw in today after work. Yes, all that cranking could have soaked them pretty good. I'll double check the connectors too. I noticed a plug or two a different colour...

Been working on American cars most of my life. I Start messing with volvos and I run into seemingly simple trouble I just can't fix. Extremely frustrating, to say the least ...

If it goes to the garage and I end up paying big buck$ for something really stupid, I'm going to be very pissed... Lol

Hopefully wet plugs is it..

Cheers,
Mike

 

So the plot thickens again and takes a different direction...

A few nights ago, I read an online account of a no-start that was my situation to a tee... In their case, the car cranked endlessly and would not start, and they later found the fuel pressure regulator, was stuck open and it just pumped gas in to beat the band..

So, I remember smelling gas so heavy, and actually seeing raw gas vapour fumes shimmering out of the down pipe... it was also making the parting line between the turbo and the exh manifold stained with wet gas as well. After reading this, it made sense to me and I set out to the heap today, to come up with another regulator. I found a good looking example and installed it later, here at home.

After the regulator was bolted on, I installed the fresh plugs and rechecked everything one last time.

So my friend gets in and cranks it over and almost 100% clear raw gas shot up out of the dipstick tube.... A big stream, mind you... not a few drops... of course it did not sputter or attempt to start and I had stopped the cranking right away. So I guess the crank case is full of gas... nice.

The mess will have to be drained and fresh oil will have to be put back in, as well as a new oil filter.

Never have I seen this before.. and yet another reason for a no start..

I guess the plugs were so washed out by the gas, it'd never run.

Ever hear of anything as bad as this before.. I haven't...

I really hope the regulator swap fixes this thing once and for all...

The engine popped a bit as well just before it quit and my buddy swears it has jumped a tooth or more on the belt.. what are the odds for that? Just something else to check... Will this car ever run again or what?

Fingers still crossed from way back..

Ill post the result..
Cheers,
Mike

 

Gas in the oil pan. I'd do a compression test as well.

 

Update...

Nothing new.. Still no spark on fully charged battery. Found rotted crossed wires at the throttle position sensor ... separated those, still nothing. Still getting spark tho.

It did manage to blow a line off of the intake that led to the electronic valve thing that is moulded into the rubber hose from the turbo. So it apparently had enough guts to fire back up thru the intake.
This led to a check of the timing belt and alignment of the marks... all is well.

BUT.. NAPA lists a crank sensor for this, tho we can find none..


BUT.... there is a 3 wire lead goind down into the pass side of the the engine block, facing towards the bellhousing.. Red, White and Black are the colours and it leads up the this mystery plug on the top of the valve cover.. refer to photo. WTF is that thing and could it pose a problem.

This thing shut off once when it hit a big bump, but restarted.

The next day it ran, got up to temp and started misfiring as the rpm went up.. and sputtering... then it just died all together and that brings it to right now.

I was reading and searching and found another suggestion of a bad brain box. Could this be a possibility? A cracked PC board in the metal case?

Anyone have a good brain for cheap? Will an non turbo "brain box" work in a turbo equipped car?

Ideas welcomed...

Thanks,
Mike

 

here's the master list of volvo 7/9 series ECUs
Engine ECU

your LH2.2 B230FT needs a -541 ECU, these are specific for B230FT (turbo) engines up to 1988. in 1989, turbos switched to LH2.4 and use completely different ECUs.