4agze missing

[beeker]

I have a AE101 4agze powing my AE86. We're using the Ae101 computer. Its a racecar and had an off 2 years ago. Its been rebuilt now, but its missing on acceleration. When you provide anything more than 1/4 throttle it starts to miss (warm). Its not so bad when cold (allows 1/2 throttle), but gets real bad when warm.

Have just drained and refreshed the fuel, issue still there. The battery is 2 years old, and is reading 12.5 volts on the multi meter, so assume thats not it (will be changing anyway).

PS Was a faultless runner prior.

Ideas please ?

[Rick]

Has it developed the miss after the repairs have been done?

[beeker]

Yes. It was fine prior, now not.
I guess there is a chance something during the repair process has caused it (disconnected something)
OR the accident
OR its the fact its been sitting there unused for 2 years.

[rollaholic]

throwing any fault codes? was it being welded with the ECU still in place

[Rick]

Was the ECU disconnected when the cage was getting repaired/added to?

Also might pay to check spark plugs/gap, replace fuel filter.

[beeker]

throwing any fault codes? was it being welded with the ECU still in place

Cant comment, was experienced repairers and cage builder (doesnt mean they didnt thou).

I havnt checked it for fault codes, i'll have to drag out my notes on that one. FYI I ignore the engine check light, as it has a permanent light due to no O2 sensor. Always been that way.

PS So welding with ECU in place casues ? damage to ECU ?

[beeker]

PS Always idles fine.

[Rick]

Welding with the ECU in place is fine but I would disconect the negative terminal and even the postive off the battery, I cant find any hard evidence that it causes problems it just seems funny how it was fine before and not now.


PS I have a few ECU's you can try if you want to see if that is causing the problem..

[beeker]

Welding with the ECU in place is fine but I would disconect the negative terminal and even the postive off the battery, I cant find any hard evidence that it causes problems it just seems funny how it was fine before and not now.


PS I have a few ECU's you can try if you want to see if that is causing the problem..

AE101 4agze ECU's ?
Mine is a: pn 89661-12790

PS You still got that rusty wreck in your paddock ? I need some hatch gas strut ends. I noticed it had some on last time i was there.

[Rick]

AE101 4agze ECU's ?
Mine is a: pn 89661-12790

PS You still got that rusty wreck in your paddock ? I need some hatch gas strut ends. I noticed it had some on last time i was there.

Yeh I got a couple of the AE101 ZE ECU's. That wreck has long gone but that was a notch back anyway, or were you meaning the AE85 I am doing up

[beeker]

AE101 4agze ECU's ?
Mine is a: pn 89661-12790

PS You still got that rusty wreck in your paddock ? I need some hatch gas strut ends. I noticed it had some on last time i was there.

Yeh I got a couple of the AE101 ZE ECU's. That wreck has long gone but that was a notch back anyway, or were you meaning the AE85 I am doing up

No there was a hatch back sitting in your paddock out back some ~6 months ago ?

Will PM you if i dont sort this out.

Any other ideas guys ?

[85AW20v]

Try new plugs and leads as well and check for any moisture down around the plugs in the head. Someone might have washed the motor a bit too much.....

[rollaholic]

i've never experienced it myself but ECU's are very sensitive to current - removing the earth off the battery will not prevent possible ECU damage, as welding passes a large current through the body of the vehicle and the ECU is earthed to the body.

the theory goes that the ECU can be damaged if the earth on the welder is not so great, and recommended best practice is to completely remove ECU's (including airbag and auto trans modules) from the car before doing any electrical welding. alot of times thats a bit unrealistic, when you consider how much work is involved in removing all that stuff from modern cars - but in the case of your car it would be a five minute job. personally i'd be a bit disappointed to find that it hadnt been done, but i do know how easy it can be to get a bit lazy about that kind of thing.

you can still check fault codes even if it has a permanent O2 fault (my car the same) you'll just have to ignore the O2 code obviously

i'd say coil packs as a instinctive response to the symptoms you describe but it would be strange for them to crap out without any use

[beeker]

update:

Checked for basic engine diag errors, and other than the o2, its error free
(note: my ecu doesnt support the advanced drive diagnostics).

Also checked the plugs (visual only, and didnt replace), and they look ok, and no residue water around leads etc.

I drove it round the block 10x, and this time it doesnt miss fire at all, just lacking power (~50% down). However, for a short few runs the power returned, but then alas it went again.

Something i've noticed is that it will not boost. The boost guage shows vacume, but wont boost. When the power did come on, so too did the boost guage. Have checked S/C oil, and thats ok. Cant see any missing hoses or obvious leaks (quick inspection only)

Suggestions ?
I'm guessing next i try ECU, then coil packs and leads.
Are the leads standard ? Can i use a set of Integra DC2 leads (got some at work)?

[mr30%jr]

i had similar trouble on my blacktop, i would be guessing its either the map sensor or the dizzy pick up.

i also remeber the speed sensor not being wired up caused a problem too.

you could bring the motor right up to 7krpm but if you tried to get there with heavy throttle it would allmost stall

[rollaholic]

i think you'll find the integra leads wont suit your coilpacks as the GZE leads use an annoying connector type. you can check your existing leads though for continuity / correct resistance range. coil packs can be checked too, someone on here might have the specs and procedure for the the GZE coils. im not 100% on GZE stuff, is the igniter built into the coils?

no boost is a bit of a problem, i believe the SC is switched off engine speed, presumably by the ECU, though i guess the clutch could be faulty too. wouldnt hurt to try another one if you can borrow one (in fact i've got one here you could borrow)

when it WAS boosting, did everything seem normal? is the SC belt properly tensioned?

[Adamal]

Sounds like a spark problem. (Thank you captain obvious!)

More to the point, it sounds like theres not enough power to make a spark jump the gap when under load.

Its a pain in the ass, but you're probably wanting to replace the coilpacks. If you know someone that has some that you can borrow, give that a go first.

[.:O4AGTZ:.]

if its missing maybe someone stole it...or in the 2 years of off time the whole engine just corroded away

[mr30%jr]

i dont think its a ignition issue. otherwise the car would have trouble running as a total

it will limp, and not recognise the throttle is wide if this not turning on the s/c and not providing spark or fuel at the correct RPM

i would be very suspect of the dizzy pick up and map.

[beeker]

Update

Took the car for a 15 minute drive tonight. The car is not missing at all now, perhaps that was the old fuel which has now drained out and has been replaced with fresh.

The remaining problem is now the lack of power, ~50% down. However, tonight is different. After 5 minutes of driving with 50% power, the power and boost came on again, and stayed on 80% of the time! for the next 10 minutes. From time to time it wouldnt kick in, and be down on power again. Its an ON OR OFF scenario, no surging or spluttering. From this perspective, I assume it must be the S/C not engaging.

Is there any chance the s/c mag clutch is not engaging propery? after 2 years on lack of use ? Anything else to check from this perspective ?