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post #1 of (permalink) Old 07-15-2007, 11:47 AM Thread Starter
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Question 1990 EFI Zuk Problem - 911 need help!

Hello all,
Long time no post, but I told you guys I would eventually be back!!...Just cant leave the Zuks alone.

My buddy and I have ran into sort of an issue with a 1990 EFI ZUK. The thing seems to start and Idle perfect, but no power when you go to take off or stomp the accelerator hard. If you bring the throttle up slowly, it does fine and rpms rise fine.
We troubleshot just about all day yesterday and I have come to a fairly simple conclusion...Using a timing light, I noticed that the engine isnt advancing when there is a drastic change in throttle position (Like stomping on the gas quickly)...When the rpms are brought up slower, the engine will start to advance later in the rpm range. I even went as far as to manually advance the timing WAY ahead in an attempt to simulate the need for high advance under load, and was able to get the mototr to run close to good when WOT (Wide Open Throttle) was attempted.
On a carburated engine, this is usually the job of the Vacuum advance...But not on an EFI rig.

I had a similar problem with a rig I got from Max (MAXNHID) when I was in NE...In that scenario, I swapped in my computer from my 1994 rig and it ran fine, so I bought a used computer for it and I was on my way.

We have chased the entire wiring harness looking for shorts, and re-taped a lot of it.
We have done Plugs, wires, oul, air filter, checked fuel flow (Shot gas all over the place)
We have checked to see if the timing belt was off by a tooth, and I do not believe it is.
We have bought a completely rebuilt computer for it from AVPROECM out of Florida, so it should be better than new.
We also got a brand New Throttle Postition Sensor (TPS) from NAPA.

Still the same issue...I do honestly believe the computer may have been bad, and now know for a fact that the TPS was as it was actually cracked...

Problem is, we are $400 into troubleshooting and have run out of money to keep throwing at it without knowing for sure exactly what the issue is...I have exhausted my knowledge base on what the actuall issue could be...Basically I am just guessing at this point and its too expensive to guess on these EFI rigs.

SO here is what I was wondering:
Im near certain the problem either exists in the Distributer, coil, igniter, or even possibly the Throttle body Injector.
The reason I say this is because these are the parts that we havent touched or been able to swap out yet...

Any idea what I could look at next??

Another idea:
Do you guys have any spares of these hanging around for us to test with or possibly even buy as spare parts for the rig??
We deperately need to get this issue worked out, and due to my lack of any EFI parts, its near impossible.
This is what I would need:
Injector with attached TPS
Entire Distributer (With all the electronic goodies inside of it)

If you dont have the parts, do you know anyone that might, Know what the issue could possibly be, or point me in the correct direction to find out?

Also, I used to have a coputerized version of the Factory Service Manual back in my days in New England (I even donated a bunch of copies of it for raffel prizes at the last GoneZukin that WildWeasel hosted)...Do any of youstill have a copy of it I couldd get my hands on again.

Thanks guys and I look forward to hearing back from you as Me and my buddy are both running out of ambition now.
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post #2 of (permalink) Old 07-15-2007, 02:24 PM
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The FSM can be downloaded here:

.:Suzuki Download Archive:.

Did you set up the new TPS properly? I doubt if the problem is in the distributor or ignitor if it sparks OK. The ECU controls the timing so the problem could be there or it could be getting false readings from a bad sensor. Have you checked for fault codes? if the ECU is in limp home mode there won't be so much advance. Also check for leaks and blockages in the vacuum pipes, particularly the one to the MAP sensor on the bulkhead. There should be an inline filter in that pipe too, check that for blockages.

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post #3 of (permalink) Old 07-15-2007, 10:45 PM
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timing won't advance...

There is a 4-pin female connector with a dust cover located near the right-hand headlight assembly. In order to properly set the idle timing, you jumper two pins - C and D - on this connector. This jumper, according to the Chilton/Nichols Total Care Care Import Trucks/SUV CD (part C3050), will "fix the timing - prevent the timing from moving". Did you jumper those pins and accidentally forget to un-jumper it?

Or perhaps those pins have been accidentally shorted together in the harness?

just a thought...

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nearly 837 searchable links to Suzuki/Geo modding and maintenence info - including the Tracker FSM Project!
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Last edited by ackerdackerly; 07-15-2007 at 10:47 PM.
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post #4 of (permalink) Old 07-16-2007, 05:58 AM Thread Starter
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Hey Ack and James,

The TPS was replaced with a new one, but no, I didnt set it as the manual said...I will do so now that I have all the manuals again...But, I know the ENTIRE throttle body had been replaced at one point (To include the TPS and Injector) and this didnt help...same issue.
I now have the service manual, so I will try chasing codes...I get no check engine light tho...As far as the MAP sensor goes, I checked it and there are no blockages. When I unplugged it, the rig stared running worse, so I am assuming it is working.

The plug I am assuming you are talking about is directly behind the battery on the firewall...I had this jumpered while we were setting timing, but I must say I saw NO noticeable difference in the way it ran when it was jumpered or not...It runs exactly the same way no matter what. This is another thing we will check to see if there is a short somewhere here.

I am also thinking to go ahead and send the ECU back to the rebuilder to get it gone thru again...Im not totally convinced that the problem still doesnt lie there and they just didnt fix it when they rebuilt it..

At this point, I agree with James that it is probably not a problem in the Coil, Igniter, or in the distributer...I agree that I cant see any of these causing and Timing Advance issue...If they didnt work, Id simply get no spark.

To all on the board:
I would be in the deepest gratitude to anyone that can either let me borrow a know good ECM or let me buy a good spare very cheap...Its almost impossible for me to rule out anything without spare parts. I literraly need to use the borrowed ECM for like 5 mins...Long enough to plug it in, check the vehicle running, then pull it back out...This way we can prove the ECU as either the problem or not without a doubt.
Ill pay shipping both ways.
I am in Phoenix Arizona now, so someone local would be preferred, but Im desperate at this point.
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post #5 of (permalink) Old 07-17-2007, 10:41 AM
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You should try over at Zuwarrie. a Lot more folks post over there so you may have a better shot. I don't have one so no help.
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post #6 of (permalink) Old 07-17-2007, 06:25 PM
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No power

I had gone through with this on my Sidekick a while back and my problem turned out to be a plugged cat. as i do not have smog inspections as this is my Nevada truck I just dropped the cat and knocked out the plugged honeycombs inside the cat. No problems and runs just fine.
You should be able to find the checking procedure in a FSM. ACK has a downloadable verson. A quick check is to remove the vacuum line from the top of your EGR valve, ( the thick one that goes to the exhaust) and rev the motor. It should have a slight vacuum on it and if it has too much presure the cat is probably plugged and I would check the cat with the FSM procedures to be sure. Good luck.
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post #7 of (permalink) Old 07-18-2007, 09:36 PM
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contact sean at Aftermarket4x4.com...Your Suzuki Specialists he may have 1 for you. i fixed a couple for him a while back. tell him redidbull sent ya. jim
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post #8 of (permalink) Old 07-24-2007, 01:02 PM
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I just fixed my Tracker that sounded like a similar problem. It ran fine, just no power!!! 45 MPH on the freeway. Paid to have it diagnosed and they got it wrong...

Mine was a plugged cat as well. Rodded out the old one before I buy a new one....runs like a new car....

I was about to tear my hair out.....

Try uncoupleing the exhaust......see if it helps.
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