Gevo

I did in fact jump the terminals, and i thought it was weird, so i went inside to confirm that the check engine light is blkinking, and it was. then i tested without jumping temrinals, i was getting exactly the same results.

I'm glad you asked, i forgot to mention this part.

What is going on here?? I'm going nuts!! It's hard to keep my cool about this..

ill go back friday to swap the distributor, see if that causes any change. Although this stock one is within fsm spec.. at least it was when i bought it....

Gevo

Have to chase that short next. I guess if its a short to one of the ecu signal wires anything can happen. But as far as I could tell it was intermittent... I dont know anything amymore. Lol. My mind is hurting from issue after issue...

Once this is all worked out, it better make me coffee and take me to many amazing places!!

Gevo

Been doing more reading on the internet trying to determine what to check next.

For the timing advancing so far and not really changing with or without te1 and e1 jumped.. I read that it is possible for a wrongly adjusted tps or an out of spec distributor to cause it. The more I think the less a 'short' makes sense to cause this problem.

I know im rambling a bit but typing it out here gives me a place to save the troublsbooting items and everyones input helps quite a bit.

I never mind to think out loud, although I have to eat my foot sometimes. Lol.

Gamefreakgc

Thinking worse case scenario here. I think I remember saying you had a friend re-wire your engine harness... might be a voltage/resistance issue with a bad/missing wire?

Gevo

Gamefreak, yes you remember right. I found the source of that initial shorting in the wiring harness and fixed it.

The current problem may be caused by a short as well, but, the timing was advancing normally before....??? . I went out again (taking lots of break from work for this!) and spend couple hours checking the distributor. I hate the new one i had purchased and it turns out my old one was in spec (bad multimeter while back) and it is better built. With it installed i can adjust the advance/retard range properly (the new distributor wouldn't let me pass about 10 deg btdc) I am getting the same result. With or without the TE1 & E1 jumped, when i'm looking at the mark with the timing light at idle it is good.. as soon as i touch the throttle the slightest bit, the timing jumps to a way advance position.

and now, drumrollll....... another TWO problems came up today. I realized that my overdrive off light was flashing when the TE1 and E1 were jumped and the OD was off. When i switched it on, the light went away, then came back when i switche dit off again. I reset computer thinking glitch, no change.

The second new problem, the PAIR REED valve VSV. I noticed some extra noises coming from the right side of the engine (passenger) and upon inspection sounded like the pair reed valve. I unplugged the vac hose between it and vsv, and it stopped.. i put my finger over the vac hose, sure enough the VSV was cycling vac on and off.

No CEL codes.

Does all this point to a short or a bad ECU? I wouldn't even mind if the ECU is bad.. i shorted the ˟˟˟˟ out of it while i was tracking down that previous short in the harness.

The thing that i had worked on between the previous timing (when everythign was working properly) and now is the dash. I took a peek underneath the driver foot area and didn't notice anything such as a short...

This is getting funkadelick... i would pay many of my dollars and beers to someone to coem and fix everything!!

muddmadness

After reading all this, I am and totally intimidated by the whole smog thing. I have to go and see a smog referee to get a bar code wuhhh???, no one told me I needed one of those...know now don't I. I do have a question about the reed valve. What is it for and what does it do? I know I have one but why???

(praying to the smog gods for mercy, lololol)

Gevo

What smog referee? Bar code? What state?

muddmadness

My Truck is special construction and does not have the barcode for emissions to tell the smog tech what equipment the engine is supposed to have. A smog referee is where they send you to get the barcode, they are the only ones that are sanctioned by the state to give out these barcodes. Once vehicle has one then you know what you need and your regular smog tech can legally smog check vehicle. State? "CA"


Don't worry you probably have your barcode, look under the hood or in door jam. Sometimes a small metal tag is applied to engine block but that's usually only foreign countries.

Gamefreakgc

Sounds like your distributor could be off a tooth. It should retard past 10*. If the distributor is off then that would cause a loss of power since your ignition timing would be off.

As far as the others, I can't say. It really does sound like you've got a wiring and/or electrical issue, the way things are all going haywire. But that's just speculation, I've done a fair amount of wiring on my rig but I don't have an auto and never had the issues you described.

Gevo

Gamefreak,

I also thought my distributor was off 1 tooth, so I took the new one that was on there, put it counterclockwise one tooth, and when i went to test engine operation, the minimum it would go to was 15 degrees btdc. Then code 52... Then I tested and put the old one back in and it is all good, adjusts from below 0 to more than the marked 15 degrees.

I just got to the truck (no garage at my apt, still working at parents house) I am gonna take some plastics off under the dash and start to trouble shoot. I studied the wiring diagram last night to determine which wires to go to check first.. the ones that are common to the various circuits. Seems like everything connects to the combination meter.. I'm starting there.

SO i'll be back to report on what i screwed up this time with the wiring. lol

Mudmadness, that is one problem i dont have... seriously, that may just have put me over the edge. lol

Gevo

I did a little experiment right now.

I jumped the TE1 E1, checked timing, idle was at 15 whre i set it yesterday. and again as yesterday when i touch the throttle even the slightest, timing jumps to way advance (guessing about 30 degrees). Although i had tested the tps and it is within spec according to the fsm, i still have doubts since i sprayed heavy cleaners over it.. so I removed the TPE connector, checked timing, it was at that ~30 degree mark. I adjusted to 15 degrees. THen, without tps connected, i throttle up and find that the timing moves up gradually with the revs... which is what it is supposed to do (right?)

I'm going to recheck all connections/wires between tps and ecu and ground.. etc.. but meanwhile, does this show symptoms of a bad tps? If i can find one in stock somewhere nearby, i'm gonna go buy it to get that out of my mind!!!

scope103

Could be a TPS issue. The lack of timing or idle change with the jumper is not to worry about; the jumper pushes you to base timing, and under certain conditions (temperature?) base timing is the same as idle timing. I don't think mine has ever jumped. But if "touching" the throttle causes a big timing change, the ECU may be getting the wrong signal for throttle position. http://www.autoshop101.com/forms/h59.pdf

http://www.autoshop101.com/forms/h65.pdf The PAIR valve squirts air into the exhaust stream, so that if you have unburned hydrocarbons they will burn up before the Cat. It's pretty bullet-proof, but over time the screws in the cover can loosen, causing a buzzing sound. Just tighten them up with a stubby screwdriver, or replace them with socket-head screws (easier to get a hex wrench in there).

Gevo

Edit:

Gamefreakgc

I just realized that you have a 91. There are TWO different distributors for that year. There's one for trucks made before August, and those after. Maybe you have the wrong type!

The distributor caps are different as well. The pre-august 91's used ones that were mirror images of themselves and the coil is bend at a 90 degree angle:



The post-August ones are "crooked" and have a straight coil connection:

.

Maybe that's what's going on? Both caps will fit on either distributor though, and both distributors will fit in either type of engine. Look at the production date of your truck to see which you should have. I had a shop install a new distributor a while back, and they put the later year one in my truck. I test drove it with them and in PINGED like nothing else. However, if you put an older one in a new truck, it may not be so bad and maybe that's going on with your new distibutor! Definitely worth checking though!

Gevo

You're gonna love this.. I have 8/91. So, does that go with the POST or PRE?

The one on the engine now (which it came with) and new one i have both are the straight, pre aug ones. I checked the part number against the VIN, and searched ebay to see some pictures. It looks like the straight one.
http://www.ebay.com/sch/6000/i.html?...ssories&_rdc=1

Gevo

I'm going to go nuts.

I've spent ALL day and can't figure out what's wrong. It's all over the place. FOr a few minutes after playing around with TPS I got the spark to advance regularly... and that stopped and it's not jumping to a way advance position again. I have a overdrive light blinking. SPoradically i get code 42, and the vsv to the PAIR reed valve is activated and stays on all the time.

EDIT: The O/D light is supposed to blink 2 times per second with TE1 and E! jumped.. oops !

EDIT 2: I just did more of the same and observed something. When I am adjusting the TPS while the engine is running, once it goes into IDL mode the VSV to the REED valve starts running continuously. When I turn it and it goes out of idle, the engine speed increases (yes TE1 and E1 still jumped) and the REED valve VSV stops. All the while when TPS is in IDL position the slightest touch of throttle jumps the timing way ahead.

I know I'm getting annoying here.. but I need to figure this out

Should I be trying out a new ECU?

Gevo

At the end of the day, I didn't get anywhere with the electrical/ecu problem.

When adjusted correctly the TPS does what it's supposed to. (Both the new and old one behaved exactly the same)
I couldn't find anywhere where the wires were shorting. I didn't pull the WHOLE harness out though, about 30% of it. I checked everywhere under the dash, near shifter.. etc...

I removed the ADD relay and the 4WD light now comes on when it should, with the relay in the 4WD light come son for a second and then goes off when it is still supposed to be on. I don't know what this has to do with engine problem... but a few times on one drive (last week) as the 4wd light was flickering the engine would lose power...examined the ADD circuitry... anyway, inconclusive...

I took her for a spin, went up the steep hill to the park and it was 'ok', pulled over and noticed the Pair Reed valve VSV was running continuously.. unplugged it and I am pretty sure it ran a bit better.. at this point i can be hallucinating.

Put about 10 miles on the car, streets and freeway.. it ran better than it had ever run before! I could smell the exhaust, but i'm not sure what i was smelling (rich or not..?) I checked timing upon return and the mark was still jumping at the touch of the throttle. Also, plugged VSV for reed valve back in.. it wasn't running. Then i gassed the engine and the pair reed valve opened up again and kept going.

The cheapest I found on ebay for a working ECu (same CA model PN: 89661-35570) is $90.

If anyone has ANY ideas at all... please share. WHen I get back from San Francisco next week I am gonna put the new ECU on it... if no good, i'm gonna drop it off at a mechanic that is willing to give it a go and pay whatever the hell it costs to get her to run PERFECT... After all this work, I will accept nothing less.

Extremely tired.. thank you all for your input and advice. Keep them coming.

PEace!

muddmadness

If you are having a problem with your timing jumping maybe its a stretched timing chain or belt??

Gevo

Muddmadness, when I say jumping im referring to the ecu advancing the timing as soon as the tps is out of its idle position. It goes from 15 deg at idel to about 30 degrees without a gradual increase

muddmadness

I see, I forgot you mentioned that in your post. Not sure if that is a better thing but probably easier to replace ECM then the other.