'89 740 B230F (USA spec) wont start.

edalbesor · Post by **edalbesor** » 22 Feb 2008, 08:16

I hope someone out there knows more about electrics than me.
I had a problem starting the engine, I had to turn it over and over for ages until it started. This got worse over a 2 week period and it was evident when the engine was either hot or cold, however it never stalled once it was running. It will not start at all now and I can smell fuel in the cylinders. I have replaced the plugs, leads, rotor and cap. Hoping it would solve the problem.
Has anyone any ideas please, please, pretty please!!!

Post by **billofdurham** » 22 Feb 2008, 11:50

Welcome to Matthew's Volvo Site.

I am assuming that this is a non-turbo engine. If so there is a self diagnostic box in the engine compartment, mounted behind the left strut assembly. Using this you can see if the engine has logged any fault codes.

To use the self diagnostics see: https://www.matthewsvolvosite.com/chat/p ... c&start=12

This is headed for the'92 740 turbo but the basic use is the same. Some of the codes are different. Read the codes and anything you don't understand post here for more help.

Bill.

edalbesor · Post by **edalbesor** » 29 Feb 2008, 06:37

Thanks for that.
Before I go any further, I should point out that I am to Electronics as Ingrid Bergman is to Rugby Union!
Mine is not a turbo, just a 740GL, B230F, US spec.
I have tried the self diagnosis wossname and so far it pans out OK ... except the one where I should "hear" the injectors doing their thing. I heard nothing and, moreover, I don't know what sort of sound I was listening for. The next thing is the ohms test on the Jetronic box.
One thought, I have a Clifford alarm on the car. I didn't fit it, I don't use it and I don't want it. Are they a DIY thing to remove and could it be the problem? When I replaced the battery after charging today the alarm went off but it was so feint! I was right next to the could only just hear the siren! Sound suspicious to you?
Thanks again and sorry for being a pest.

Edalbesor

Post by **jonesg** » 29 Feb 2008, 09:33

Try a quick swap the relays on the coolant bottle bracket, one controls the injectors and mine did fail like that without any code.

Another suspect is the sensor on top of the bellhousing which falls apart due to engine heat, look straight down with a flashlight.
If the tach is dead when the engine is cranking that sensor is dead.

You replaced lugs wires etc, but are you getting spark?
Use an old plug (cleaned) to test for spark if you don't have a light.

edalbesor · Post by **edalbesor** » 29 Feb 2008, 10:13

Thanks again for your help guys.
One possibly relevant piece of information is that about a month before the trouble started I had to stop when the engine overheated. I had a small leak in the coolant system which, over the years topping up, had diluted the anti-freeze. The coolant liquified and I went on until I got to buy some anti-freeze. Could the over heating have caused the non-start problem I now have? I hadn't connected the two until your comment on sensor on the bellhousing. BTW - what does it look like?
A mechanic did take a look for me but he's a diesel man and doens't really get 12v electrics. He said there was only occasionaly a spark at the plugs under cranking. (He is French and I am pretty sure that is what he said!)

Post by **jonesg** » 29 Feb 2008, 17:34

Occasional spark eh?
I wonder why it won't start.

The likely suspect is the sensor on the bellhousing

looks like this,

http://www.brickboard.com/FAQ/700-900/E ... ion_Sensor

As I wrote, get a flashlight and take a look.

run your hand down the wiring , you'll probably find the cable is knackered down by the sensor. I think its a 10mm bolt, you need a socket with a short ext, a universal joiont and a 12 inch ext, once loosened unscrew it by hand (do this from the top), you don't want the bolt to drop inside anything down there. Its a 2 minute swap job of a $29 part.

I changed mine but the problem turned out to a fuel pump, but from the state of the part and the wiring it wouldn't have lasted too much longer anyway.

edalbesor · Post by **edalbesor** » 04 Mar 2008, 08:10

I located the sensor and, as you had suggested, the outer sheathing of the cable was broken (in fact, missing for about 2").
I disconnected the plug and tested it. I got 450 ohms between the centre pin and one outer and nil on the other.
After reconnecting it the engine started and ran for about 3 seconds when it just died. This was repeated over and over again. I tried re covering the cable with some insulation tape but it didn't do any good, she still runs for a few seconds. Do you reckon the actual sensor itself is wrecked?
I can only find one Volvo in the breakers here and, dammit, it's a turbo 740. The sensors (2 of them) are different. I can get a second hand one sent out from the U.K. but I wanted the opinion of someone who knows before I arrange it.
Thanks again.

Post by **jonesg** » 04 Mar 2008, 17:37

At this point it could be a number of things, it depends whether you want to test or just start swapping parts, the bellhousing sensor isn't going to last long anyway and ought to be swapped whther its the cause of the no start or not. It soon will be a problem. Because they are known to fail due to a hot location buying used is like installing used spark plugs, ok to get you home but not a proper fix.

If you have a voltmeter connect it to one of the injector plugs and watch the needle as you crank the engine, hook it to the injector nearest the windshield and run the wires under the hood, put the voltmeter on your windshield wipers so you can watch the needle as you crank it over.
Set it on the low v range and just look for a deflection, if nothing , reverse the wires because it might be backwards.

Running for 3 seconds could still be the injector relay, (the one on the coolant bottle) and it could also be the fuel pump relay under the ashtray.
They are notorious for heat failure, solder joints crack but can be easily fixed or replaced.

My 740 had the same symptoms for the injector relay, hard starts then eventually a no start situation.

BUT, when my fuel pump was going bad the symptoms were the same too.

So its a matter of swapping parts by guesswork or isolate the problem.
Have you tried spraying some ether in the vac line on the front of the FPR (on the fuel rail).?

Unless the mechanic has used a fuel pressure guage on the fuel rail I wouldn't assume you're getting good pressure either, my bad fuel pump still pumped fuel out when I cranked the engine over but it wasn't enough pressure, a good shot of ether would tell you if its starving for fuel.

edalbesor · Post by **edalbesor** » 05 Mar 2008, 00:19

Ah, thanks for that. I have come back to earth now! I replaced the fuel pump relay as a first thought. The symptoms said to me it was a fuel problem but when the mechanic said there was only occasionally a spark on cranking I was then convinced it was an electrical problem. The last time I tried it there was no life whatsoever, like before it would crank but nothing happened. When I tried testing the connections on the RPM sensor and then re-connecting the plug it started and ran, ableit for 3 or 4 seconds. This convinced me that, as the only component I had fiddled with was the sensor, that "must" be the faulty component.
Anyway, as I said at the start, I'm an idiot where electrics are concerned and I am undyingly grateful for your kind help. Maybe it will become a process of replacing everything until it runs but run it must.

Post by **jonesg** » 05 Mar 2008, 11:06

Watch your tach when you crank the engine , if it doesn't move the RPM sensor is bad.

And don't be surprised if you change it and the damn thing still doesn't run, sometimes problems create a domino effect with other parts and 2 things go bad together.

Cheers, Gerard.