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99 Tracker, 5 door, 2L, 4x4
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It seems redundant to go chasing additional codes if the issue with the 5v ref is not rectified first..

I would connect (Back probe) to the 5v REF at the ecu then disconnect all sensors accessing the REF until the 5v stabilizes..
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #22
Thanks Aquanaut

I thiiink I have all the sensors unplugged now. Gotta doublecheck the map. 3 questions.
-If my problem is in the wiring to a sensor will disconnecting them rule the wiring to them out??
- not sure what you mean black probe to 5 ref. I’m New at this
-if I do find the bad sensor. I don’t need to reset the comp— unplug the dome— for it to start showing right do I?

Thanks for y’all time

Ok one last one.
- In case I never get this figured out.. does anybody make an intake for this lil beauty that will take a carb?
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #23
Ok

I stillll cannot find the map or the iat sensor. Like I said I checked the wiring right at the back of the ecu and cannot find grey/green or or red/black. Should these run all the way to the back of the ecu?? I found a connector right near the ecu that changes a red/black to a grey/green? Could that b it??? The map sensor should have a vacuum hose to it?? Uh. Also I disconnected the harness at the front of the engine right before it runs next to the fuel rail. Caint find grey/green or red/black. Did test the grey/red wire there and it still falls off...so does that help me narrow anything down maybe?? And Bex. I did check those codes once already in a previous post. It stayed with21 code. Would you recommend checking again? Could it be something else. Like the ecu power or ground?? I did check those but can check again being new at this maybe I missed something.

Thanks for letting me bombard you guys with all these questions
 

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99 Tracker, 5 door, 2L, 4x4
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The IAT would be part of the MAF sensor Located in the intake tube.

That is BACK probe as opposed to BLACK probe, (the act of inserting a pin/probe into a connector)

Many times the OE changed colours in harnesses, especially when/if change of supplier.

Yes it is possible to be a main ground or power to the ECU that is failing, that is why you must load the circuit when testing..
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #25
Ha

BACK .Not BLACK. Missed that one. Ok. Thanks Aquanaut. One more quick I know you answered this one before but I have no idea how to “load the circuit” to test it? Rookie guy here
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #26
Ha

BACK .Not BLACK. Missed that one. Ok. Thanks Aquanaut. One more quick I know you answered this one before but I have no ihow to “load the circuit” to test it? Rookie guy here
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #27
Ahhhhh

One more. I see the MAF. It has three wires. Blue/black black. And gray/black. The closest wiring diagram I can find which happens to be in my chilton book says it should have the grey/yellow and red/black. There is definitely only the maf on there and to my understanding if it doesn’t have the shared ground...grey/yellow then it shouldn’t affect my 5v ref circuit anyway. Again Caint find map or iat anywhere. I do have a sensor that to me miiight could be the map on the intake manifold but it is a 2 wire not 3 and completely different colors and definitely no grey/yellow wire. Make any sense that I don’t have those 2 sensors?? Or am I just blind.

Thanks ?
 

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first of all, toss the Chiltons away. They are not accurate manuals.
 

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I was looking back over the posts to see if there was something that I could add to help.

Not really, but I have a comment.

"91 sidekick 4dr 4x4 16v 1.6l manual transmission efi. "

Very rare beast, no wonder you are having problems finding wiring diagrams that match it. This was the first year for the 4 door, at least in the US market. Most 1991 4 doors came with the same drive-train of the 2 doors. (And there wasn't very many of them.) They mostly came with 8v motors and the automatics were 3 speed, non- computer controlled.

My 1992 16v did not come with some of the sensors you seem to be looking for. It did not have a IAT. I also don't think that the US market 16v has a MAP as it uses a MAF. (8v motors have a MAP on the firewall.)

OBTW... Chilton's and Haynes manuals try and cover way to many years and models to be of much use. Be VERY careful with the information you use from them.
 

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Ahhhhh

One more. I see the MAF. It has three wires. Blue/black black. And gray/black. The closest wiring diagram I can find which happens to be in my chilton book says it should have the grey/yellow and red/black. There is definitely only the maf on there and to my understanding if it doesn’t have the shared ground...grey/yellow then it shouldn’t affect my 5v ref circuit anyway. Again Caint find map or iat anywhere. I do have a sensor that to me miiight could be the map on the intake manifold but it is a 2 wire not 3 and completely different colors and definitely no grey/yellow wire. Make any sense that I don’t have those 2 sensors?? Or am I just blind.

Thanks ?
That is a wrong assumption, The REF circuit is the important one, and the signal, the ground side may have an engine ground or return to the ECU for monitoring...
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #31
Hey

Thanks mooooo. Well that’s another clue anyway. Maybe that will help me find a better diagram. The chitons so far has been the best it actually matches the wire colors that I have at least as far as I’ve seen. It just shows and everything else I’ve seen shows that I have the map and iat sensors but I caaaant find em. Looked all over the firewall but I got nutn.
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #32
Ok guys.
I have an idea. What do y’all think

Start at wiring harness connector to the ecu. Pull one wire out of the harness connector at a time and check for my ref voltage to come back. If not then put it back and do the next one. Minus pulling any of the grounds. Or at least the ecu ground and power.

What do y’all think of that?
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #33
Mooooo

I read yours again. Got it. Looks like I don’t have either iat or map. Thanks for that.
 

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Testing for voltage is not decisive, a bad connection will carry voltage.. use an automotive incandescent test light, that will LOAD the circuit, if good will glow and voltage will remain, if bad light is black and voltage will drop...

So, meter and light to ground, connect +meter to circuit (see 5v), with meter still connected, touch + meter lead with test light.. If meter still sees 5v, circuit is good..

This is how to load a circuit, the load (test light) draws amperage..
 

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While this won’t help with the electrical questions, here is the parts catalog for the 1992 Suzuki Sidekick. If you look at diagrams specifically indicating 4 VALVE (which is the 16v engine), you’ll see what appears to be your engine - for example, there is a MAF on the engine diagram, etc. Sadly, it doesn’t show wiring (or at least colors, etc.) but trying to find a 1992 Sidekick factory service manual may help you in the future.
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #36
You guys are awesome. Ok I’ll load test -thanks Aquanaut—the wires that I KNOW are in the ref circuit before I get crazy on the harness and try to find out if there’s anything other than the tps and ect sensor on that circuit. Thanks Bex.
 

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Discussion Starter #37
Ok you guys. Still at this stupid thing
i obviously don’t have to have this thing running but I’ve got alot of time and money invested in it at this point and I’m either going to get it or set it on fire! So got my brother up to help me. Bought a fsm for the car. One used ecm.... ran for a week. One rebuilt one... 3 weeks. Checked every wire at the ecu they all read what they’re supposed to. Load tested all the wires to the tps and the shared sensor wiring...all tested good. It blew my first used ecu. Bench tested it still wouldn’t pull 5v on the ref wire( grey/red. Had it rebuilt thinking maybe was screwed to start with and it dropped the ref wire again sitting there warming up. Have unplugged ALL other sensors and still Caint get it to come back. Am thinking I’m getting a voltage spike? Screwing up ecu? Uh bad voltage regulator. I’ll watch that and see. Thought I would hardwire ecu power and ground. Add a switch on power. Maybe that will help it handle a spike if it’s getting one? Any ideas? Anybody wanna come check out Alaska??
 

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check for chafed wiring, or frayed insulation in laymans terms, what you are describing can be caused by intermittent shorts in the loom, especially +12 to the 5V reference rail.
 

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91 sidekick 4dr 4x4 16v 1.6l manual transmission (mpi)
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Discussion Starter #39
Roger that mr. hope that’s what it is. Think I’m just gonna rerun the power to the ecu. Bypass the relay too n put it on a switch. Or do you mean another 12v wire chafed onto the the 5v ref wire or circuit? Seems I would have found it by now. As far as my eye can see there isn’t anything rubbed in the harness. Maybe I could rerun all the wires to the tps also just in case. More likely a crossed wire with the tps circuit (and or all the wires involved) or something causing a voltage spike?
 

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Possibly, about the only thing that kills ecus is volts where it shouldn't be. . You have a big capacitor absorbing most of, but not all the spikes in the form of the car battery. The reference rails are well filtered in the power supply of the ecm. If 12V gets into the 5VDC reference circuit the ecm will pretty much die. Losing a ground to the ecm or in the sensor reference circuit can cause similar issues.
Running new supplies and reference circuit supply is a good idea as the looms can degrade over time and a chafed wire could still be buried in a wrapped section if the loom.
 
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