1989 740 won't idle

[griston64]

1989 740 2.3. Car starts and runs but won't idle. Cuts out every time you stop. it's not my car and I haven't seen it so this is all info from the current owner. He said you would need three legs to drive it

The issue started after the car ran out of fuel and he said he has replaced the injectors and put on a new alternator but issue remains ( i'm guessing its neither of those things anyway) Thinks it could've sucked a load of muck up from bottom of tank but ( and my knowledge is limited ) if that was the case it wouldn't start and run.

Any ideas ? I'm planning on buying but would like to be able to sort the issue so I can drive it home

Cheers
Mark

[john.wigley]

In my experience of 740s, Mark, an erratic idle is much more likely on carburetor fed rather than fuel injected cars.

According to Haynes, an erratic idle on FI cars can be down to the following:
1. Misfiring (Ignition fault)
2. Induction air leak.
3. Fuel distribution control plunger sticking.
4.Throttle valve(s) loose or worn.
5. Injector(s) leaking or poor spray pattern.

Based on the above, and that the owner has recently changed the injectors, I think point 5 would be the best place to start looking for the cause. The other points are all likely to have been pre-existing and therefore evident before running out of fuel, although it is not impossible that sucking up gunge from the tank may have caused some components to stick, I guess?

Regards, John.

[aardvarkash10]

failure to idle all the time? Cold? Hot? On over-run?

What fuel system SPECIFICALLY?

Why was the alternator replaced?

Why were the injectors replaced?

What wheels does it have? (just kidding - this really isn't relevant, I'm just being nosey)

[griston64]

Thanks John

I think I'll go and have a look this weekend and can than perhaps report back with a more accurate description of the fault. From the owners description it seemed as if the car doesn't idle at all.

Cheers Mark

[Laird Scooby]

Mark - in addition to the questions Ash asked, when the injectors were changed were the "O" rings renewed and were the injectors new or secondhand?

Also is it a B230E (K-Jetronic) or B230F (LH-Jetronic)? Is it also a pig to start compared to before?

Got a few suggestions but would be helpful to know the answers to what Ash asked and my questions to help make the decision.

[griston64]

Cheers Dave

As Manuel would say " I know nothing"

I'll go and view car this weekend and come back with a detailed report

Cheers, Mark

[Laird Scooby]

Originally Posted by griston64

Cheers Dave

As Manuel would say " I know nothing"

I'll go and view car this weekend and come back with a detailed report

Cheers, Mark

If you're thinking of buying it Mark and want to drive it back, take a gallon of petrol (i suspect it's probably low since he ran out), 2L of meths (Toolstation is about the best on price) and either a good quality injector cleaner or 50ml Carlube ATF-U - other synthetic ATFs may work too but i haven't tried them.

Assuming it has 1/4 tank or less, add half the fuel from the can then add the ATF and meths to the remainder, give it a bit of a shake to mix it and add that to the tank too.

This should work its magic as you drive and is assuming that it drives and pulls ok and the idling is the only problem.

After that we'll have to wait for your detailed report to advise more. Hopefully it should be sorted though!

[griston64]

Originally Posted by Laird Scooby

If you're thinking of buying it Mark and want to drive it back, take a gallon of petrol (i suspect it's probably low since he ran out), 2L of meths (Toolstation is about the best on price) and either a good quality injector cleaner or 50ml Carlube ATF-U - other synthetic ATFs may work too but i haven't tried them.

Assuming it has 1/4 tank or less, add half the fuel from the can then add the ATF and meths to the remainder, give it a bit of a shake to mix it and add that to the tank too.

This should work its magic as you drive and is assuming that it drives and pulls ok and the idling is the only problem.

After that we'll have to wait for your detailed report to advise more. Hopefully it should be sorted though!

Cheers Dave

I was going to take some petrol so will add the meths and atf. I was also wondering if cleaning throttle body might help as well ?

Cheers Mark

[Laird Scooby]

Originally Posted by griston64

Cheers Dave

I was going to take some petrol so will add the meths and atf. I was also wondering if cleaning throttle body might help as well ?

Cheers Mark

It might but how easy that would be to do is another matter! If it's the B230E, you'll get a shock when you look under the bonnet!

In all honesty, that's a fault that would have been there a long time so assuming what the seller said is right, wouldn't have happened as a result of running out of fuel. He could be working a flanker and telling you one thing when that isn't really what happened, however idling problems can generally be sorted easier than running problems.

If you like the car and can drive it home balancing it on the throttle to keep it running (if the magic potion above doesn't do the trick) then i'm sure we can get you (and it!) sorted.

[griston64]

On re reading his text he mentions that that injectors were totally blocked and he replaced them with Bosch ones at £80.00. He doesn't mention if that's per injector or for all four. If all four that would suggest second hand.

I'm going to see Saturday so all will be revealed on Saturday night