V8 hesitating

Tubes63 said:

Standstill in neutral, the engine revs fine. If I open the bonet and operate the throttle from in there then when I give it a sudden bout of throttle you can hear a sort of spraying noise before the revs pick up but I seem to remember that this is normal.

However, if the engine is stone cold then the it will hesitate for a second before revving, which leads to quite an annoying ride for about ten minutes.

I haven't checked my ignition timing, but that's a pretty heavy duty job isn't it? I haven't got the skill nor the patience to do that haha (not to mention the tools). Suppose I could get a garage to do it.

Click to expand...

The slight hesitation you describe could very well be down to ignition timing.

Checking timing is actually quite easy, all you need is a strobe light. I am a bit too far away to offer to check it for you I'm afraid.

The other way to get an idea of where the timing is set is to check it statically. What you need to do is turn the engine by hand and line up the timing so it is at the correct angle BTDC (4 degrees I think for V8 but would need to check), then pop off dizzy cap and see if rotor arm is pointing at the pick up for plug No 1. Remember, dynamic timing (with strobe) is a better way to set ignition but static timing should get it there or there about.

The other option is to set it "by ear", get the engine warm and carefully adjust the position of the distributor, after each adjustment, grab the throttle and quickly open to wide open throttle, see how quickly the revs pick up. Then test drive, listen out for pinking or poor responses.

Yeah it could easily be timing. A lazy engine is probably not advanced enough.

Strobe light really required to sort of confirm that what you have set by ear is sensible, but yeah it can easily be done.

Tbh you basically want to rotate the distributor as far anticlockwise as you can without it pinking.

I think that because my timing gear is worn I have got my dizzy set as far as it will go anticlockwise (vac unit close to water pump) and it still does not pink.

Alright tomorrow is "buy a timing light" day haha. Am I right in thinking that the car should be warmed up before the timing is checked?

Cheers guys

i didnt think it mattered as such but yeah you might aswell set it at operating temp.

you are better trying to borrow a good quality old skool one, something decent with a strobe not a simple filament lamp. i have a 30 year old snap on that works superbly

Just read through and caught up with this thread...
Conclusion...

Your distributor is fook mate !.

Take it out and either replace with a known good s/h one, or a new/recon one

joe1972 said:

Just read through and caught up with this thread...
Conclusion...

Your distributor is fook mate !.

Take it out and either replace with a known good s/h one, or a new/recon one

Click to expand...

Thanks for taking the time mate.

I'll bear that one in mind, I guess at the very least it can't HURT to have a new distributor right? haha

I'd have to save up though if you're talking about the whole distributor and not just the cap... as said before I'm saving cash to pay for the summer :doh:

If your truck is a 93my UK spec one it will have oxy sensors and cats.If this is the case you must find the cause of the misfire and sort it out.This will be why it is stopping,the misfiring cyls will give the oxy sensor on that bank a rich signal.Then the ecu will see it and lean off that bank till its so lean the other 3 cyls will be so weak they make little power at all - turn the steering wheel etc/have lights on and it will pull enough power from the engine to overcome it.
Misfires are the BIGGEST enemy of closed loop petrol engines.
Find a different garage,any decent indy will know about the little 5 pin plug that the 14 CUX EFI system you have for diagnosis.

My 92MY non cat doesnt have the diagnostic wiring in the loom, the pins are at the ECU but would have to be connected up.

We're closed loop versions fitted with OBD plug as standard?

Mr Noisy said:

My 92MY non cat doesnt have the diagnostic wiring in the loom, the pins are at the ECU but would have to be connected up.

We're closed loop versions fitted with OBD plug as standard?

Click to expand...

No,none of them used the 16 pin OBD plug for engine diagnostics.The plug WILL be there unless its been cut out,its a 2+3 plug with round pins about 10-12" along the loom from the ecu plug.

I'll have a look cos I've always been interested but im sure the pins are at the ECU but there's no wires to them, as far as I remember!

stu managed to hook up my 1990 to his orginal 90's diagnostic tool so they must be there noisy

Mr Noisy said:

I'll have a look cos I've always been interested but im sure the pins are at the ECU but there's no wires to them, as far as I remember!

Click to expand...

I'm sure the diagnostic plug will be in there somewhere, my 91 RRC (non-cat) has one but as eightinavee says, not OBD.

Tubes63 said:

Thanks for taking the time mate.

I'll bear that one in mind, I guess at the very least it can't HURT to have a new distributor right? haha

I'd have to save up though if you're talking about the whole distributor and not just the cap... as said before I'm saving cash to pay for the summer :doh:

Click to expand...

The distributor is relatively simple, you could probably get it refurbished. You can certainly strip it down and check the bearings and centrifugal weights (bob weights) and that the base plate moves freely and the vac unit is sound.

Just remember if you disassemble the distributor don't loose the springs and also you will need to re-set the pick up air gap.

You don't have to reset the air gap if you remove the hall effect sensor and base plate in one. If you remove the sensor from the plate then it needs a reset. That was the case for my 35DLM8 anyway.

Regards the diag, ok I will have a look today if I remember! I'm sure as sure, and I've been a fair way down the ECU loom anyway cos I've used the wiring for a few mods, so I think I would have seen it.

I was under the impression that RRC had the plug, others were optional.

Steve Heath website says that most have it but not all.

Anyway, will find out for sure!!!

it was under the seat he plugged it in

Or, for about £100 you can get yourself a brand new dissy unit off ebay. stops atleast some of the messing about....sorry to be a killjoy!

If I can't find a cheaper fix I'll have to get that dizzy then joe. Thanks for your help.

But a revelation came today... Now that I finally bought a powerful torch (was working off the light from my phone before) I can see that the hose from my plenum chamber to my fuel pressure regulator has had a split, which has been sealed up with some green/blue sealant crap at some point. I can still see a little bit of the crack (about 8-9 mil) on the outside of the pipe which isn't covered by sealant. Could this be the answer perhaps? God knows why you'd seal that pipe instead of replacing what is probably £2-3 at most!

What do you think?

I also cleaned the throttle body with carb cleaner. Waiting for it to dry to start up.

Cheers boys

Well gents, just got word from my mate who's been taking a look at it while I'm in China (and who has proper diagnostic equipment), and aparantly the problem has been solved.

According to him, a temperature sensor on the exhaust was working, but the wire to the ECU was bad, so the ECU was under the impression the car was constantly cold, meaning she was burning about 40% rich! Never would have guessed that, but there you go. I won't know if it is 100% fixed until I get back and drive the old girl, but it sounds good to me!

wish you had said it had lambdas!, mind you you may well have and I missed it

fett said:

wish you had said it had lambdas!, mind you you may well have and I missed it

Click to expand...

I didn't think it was something I had to explicitly say haha... Only realised how "modern" they are when the AA man asked if it had them! But oh well, I think Noisy probably told me to check them a long time ago and I probably never got around to it