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**geoffinbc** · 11-02-2003, 02:14 PM

Can you scan the ECM with a scan tool?.. There may be a timing issue and you are not getting proper advance. Also look for a knock sensor signal. Thoes unplugged wire sound strange..better look into that.

**jmgtp** · 11-02-2003, 03:58 PM

I dont have a scan tool

I wonder if autozone has a scan tool that they could throw on if I bring the car in. Ya I dunno where that mystery harness goes! Ugh, I wont be home again till Thanksgiving anyways

**Anonymous** · 11-02-2003, 06:19 PM

You should have taken a pic of the wire harness, that way someone could have recognized it. I'm 99% sure AutoZone will scan your car for free--but I think it only looks for trouble codes--which you said there are none. Unless you can get your hands on a scan cable somehow (I thought you had one?), its gonna be hard to diagnose.

**jmgtp** · 11-02-2003, 11:27 PM

I was gonna take a pic but couldnt find the sis's digicam

Black harness, 2 green wires (cant remember if it was the male or female end tho) or where it came from (might have been from the same group of wires as wires for the injectors, cant remeber!)

**Cliff8928** · 11-02-2003, 11:54 PM

Re: Still Runs Poorly... ??

Originally posted by jmgtp

Oo ya... on the firewall side of the engine, where the wire harness for the injectors is, I noticed a harness not plugged into anything, it has 2 green wires going into it. Should this be plugged in somewhere? I couldnt find anything to plug it into. I measured no voltage at this harness while the engine was running.

Does your car have a digital instrument cluster?

Cliff Scott
89 BerettaGT
89 Volvo740

**jmgtp** · 11-03-2003, 09:24 AM

Re: Still Runs Poorly... ??

Originally posted by Cliff8928

Does your car have a digital instrument cluster?

Cliff Scott
89 BerettaGT
89 Volvo740

Yes. If by digital you mean the cluster seen in this pic (from beretta.net -not my car but same cluster):

http://www.beretta.net/model_info/images/90greenindy.jpg

**5speedz34** · 11-03-2003, 01:10 PM

Did you try the plugs cuz some plugs might not work to well w/ur engine such as the bosch +2's for the DOHC. Maybe something w/the crank sensor or knock sensor?

**Cliff8928** · 11-03-2003, 02:15 PM

I know exactly what that plug is for, and you don't need it.... It's used for the temp sensor for the gauge on analog instrument cluster equipped cars (the sensor in the corner of the head).... The digital equipped cars don't need it because they receive the temperature info via the ecm as serial data..

Cliff Scott
89 BerettaGT
89 Volvo740

**jmgtp** · 11-03-2003, 04:10 PM

Its not the plugs. I put in rapid fire #6s, pregapped (i checked them anyways) and it ran like hell. I took them out and popped the old plugs back in just to check to see if the plugs were the problem, but same effect. So that harness is ok. Damn. What the hell is goin on with this thing?? I think the autozone 'scanner' only reads codes too. Where can I get this thing on a scan tool that will tell me everything the ecm is doing / seeing?? preferably for free! and definetly not at the dealer!

**5speedz34** · 11-03-2003, 04:44 PM

Well, to get it on a true scan tool you would have to know someone or take it to a diagnostic shop. BTW- were are u located?

**geoffinbc** · 11-07-2003, 01:13 PM

A dealer will do a full scan on your car with a TECH1.

**v6h.o.** · 11-07-2003, 02:20 PM

plugged catalytic converter.

bad/poor ground

knock sensor issues. with bad knock sensor wiring or sensor it can retard timing full on and make it have no power and run funny. (happened to my car)

hmmm. im trying to think what else could be causing this... does your car have a MAF setup? check to make sure the maf is working properly.

if i think of anything else i'll post it.

**jmgtp** · 11-07-2003, 05:51 PM

Originally posted by v6h.o.

plugged catalytic converter.

bad/poor ground

knock sensor issues. with bad knock sensor wiring or sensor it can retard timing full on and make it have no power and run funny. (happened to my car)

hmmm. im trying to think what else could be causing this... does your car have a MAF setup? check to make sure the maf is working properly.

if i think of anything else i'll post it.

thanks for the suggestions.
The engine uses a map sensor (I believe they dropped the maf after 88 for the 2.8/3.1 but not sure on that, either way this one is map and I swapped map sensors with the one from my dohc just to eliminate it as a cause - but ran the same even with the known good map from the dohc). A plugged cat converter would make sense, but the fact is that it ran fine until the moment I changed the spark plugs/wires (and I'm positive the new ones are good, tried 3 diff sets of wires!), so that leads me to believe the cat is still ok. I suppose I could unbolt the exhaust at end of the downpipe and take it for a quick (likely earbleeding) spin around the block to see if it improves. There are no trouble codes stored in the ecm. I'm really starting to lean towards either clogged fuel injectors or knock sensor issue. How can I check the knock sensor and the wiring other than a visual inspection to see that the wires look ok? I dont have access to a scan tool.... which would likely tell me exactly whats wrong

Heres a crazy, crazy idea... I dont have spare 3.1 injectors. I do have plenty of spare dohc injectors though... I think you know where I'm goin with this... so even tho the dohc injectors would likely run ultra rich and not have the correct spray pattern for a single intake valve BUT if the stock 3.1 injectors were bad and infact causing this problem I *think* it would run better on the 3.1 injectors (as this beast seems totally starved for fuel unless it turns out to be retarding spark like crazy). Would running the dohc injectors be harmfull? besides the fact that itd be super rich and I'm sure the cat wouldnt like that.

Are there any wires running behind by the rear spark plugs / alternator area that would be sensitive to a light jossling? I wasnt the gentlest back there when removing/installing the spark plugs.... maybe I knocked something loose? The only wires there seem to be the FI harness, alternator hook up, and an unplugged harness which we have determined to be for the analog gauge cluster only (car equipped with the digital gauges so this harness is unused).

**v6h.o.** · 11-07-2003, 07:05 PM

the crank sensor and the knock sensor are both on the backside of the engine, but are on the block.

as to the knocksensor...well its easy to watch with the scan tool. hmm.

the knocksensor is a one wire connector, with a ugly big goofy plastic retaining connector. hard to explain. looks kinda like a lamp shade i guess. a mini lamp shade LOL.. i dont know how to explain it.

the crank sensor i doubt you would get at from just trying to do plugs. its a two wire connector.
there are also ground wires down at the transmission bellhousing/engine area as well.
thats pretty much it for wires down around there.
however there are wires up around the plenum that could have been mucked with when trying to get down back there. quite a few wires.

as to the injectors. i dont know for sure on if they'll work decent enough to test the engine.

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Still Runs Poorly... ??

Still Runs Poorly... ??

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