Hesitation problem

[IGottaSy]

Any fault codes present? If so, disconnect the battery for a few minutes. My 1995 GMC was stuck on limp mode even after I got 12v to the 4l80e due to bad wiring. The reason is that it must go thru a few ignition key cycles before it resets itself. Disconnected battery and its shifting thru all the gears again.

 

[Mephisto]

Any fault codes present? If so, disconnect the battery for a few minutes. My 1995 GMC was stuck on limp mode even after I got 12v to the 4l80e due to bad wiring. The reason is that it must go thru a few ignition key cycles before it resets itself. Disconnected battery and its shifting thru all the gears again.

The frustration continues!!!

The distributor I ordered from Summit showed up and the one they sent me was for a 2nd Gen S10, which was huge. So I had to send that back.

I decided to order a new set of wires first, just to rule those out for sure before I try reordering another distributor. Unfortunately the MSD wire set is discontinued, so I had to order a set from Sportmachines, only to find out they're relocating and still haven't shipped the wires after waiting for 2 weeks.

I have to get this POS smogged this weekend, and can't wait for the wires from Sportmachines, so I had to order another universal set from Summit, which showed up today. Got those put in tonight, and just as suspected, no difference... so at this point I'm just gonna have to throw some race gas in it, pull the power on the IC pump to get the intake temps good n hot, and hope I pass smog. Cause this thing reeks at idle. Bad.

I did come across my old Ultimate chip and Ostrich in a box in the garage last weekend... I could never find a 3bar/50# bin online to reprogram my Ultimate when I got it, but, I just came across one on Tooky's old website. I'll try reprogramming that chip this weekend and swap it with the TurboTweak chip just to rule out that as well.

I'm not entirely sold on the distributor being the problem because there's just not a significant amount of play in the distributor for me to think it's the problem. Especially after I already swapped the cap/rotor, ICM, and coil...

If I rule out the chip and the distributor, what's left? Another ECM?

In addition to this BS, I have to replace the AC compressor and the water pump, so I might as well pop the valve covers off and check the valves while I'm at it.

I don't think there's ever been anything in my life that I've hated more than this truck. Not even my Syclone, or my cocaine cum dumpster exgf from like 10 years ago. But now (courtesy of Audi), my Ty is my daily driver, and I often sit in traffic fantasizing about this truck just going up in flames, while I watch with the utmost gratification as it dies a slow and horrible death in the middle of the 101 among tens of thousands of angry commuters. If I didn't think I could get at least SOME of my money back from it by selling it, I would've set this thing on fire a long time ago and done the world a favor.

Oh yeah, and to answer the question in the quote... I don't have any fault codes, and the CEL isn't on. I've already tried pulling the ECM fuses, disconnecting the battery, pulling the chip and reseating it... all with no improvements. I could loosen the fuel rail and see what "accidentally" happens there... that just might fix ALL my problems at once!

 

[IGottaSy]

Alright, I suppose no damaster file or similar available to see what is happening with the electronics yet.

1. Fuel pressure setting at idle vacuum hose disconnected?

2. IAC clean of build up carbon?

3. MAP matches chip(2 bar-stock, 3 bar)

4. TPS reading 0-5v? (Key on, engine off idle-WOT)

5. No vacuum leaks? Spray starting fluid anywhere you have vacuum hose connection. It will sputter or stall depending on vacuum leak severity. Injectors seated tight?

6. Fuel injectors match ECM ( impedance) ?

7. Is ECM taking a reading from the Wideband?

8. Stock O2 sensor in place?

9. knock counts out of range or excessive? Because of ticking...

Ticking sounds like injectors to me, normal. ECM should still be ok but could also have injector driver damage. Wouldn't hurt to try one known good but do make sure your injectors are the right match. My truck just got bitten by the CEL bug. It's a conspiracy!

 

[Mephisto]

I have a datamaster file I posted but my apparently the link I posted from my WD mycloud, doesn't work to download it.

I got the stethoscope out today, and found the noise. It's coming from the injectors although I can't really tell exactly which one, cause it sounds like it's coming from all of them haha. When I touch the stethoscope on an injector or on the fuel rail and advance the throttle the buzzing actually sounds/feels like a relay chattering. Can injectors arc? I don't even know what I would check that would cause that. It could be coming from one injector and I'm just hearing/feeling the chatter resonate through the fuel rail?

Here's the answers to your questions, and thank you for bearing with me through my frustration here...

1. 42psi
2. New replaced about 3k miles ago
3. yes
4. yes
5. pulled turbo/IC hose off and did the bike tube trick, only a slight hiss coming from below the TB.
6. I believe so, emailed with Eric and my TT chip is programmed for 50# MSD injectors
7. yes
8. no, WBo2 is in its place
9. no

I'm going to check the ohm resistance on the injectors tomorrow just to see what's going on there.

What would we ever do with all our free time if we didn't own these god forsaken trucks??? haha

 

[1blkc4]

I remember reading something about adjusting the fuel rail height to prevent metal to metal contact the fuel rails are slotted .

 

[IGottaSy]

I would concentrate on these.

"5. pulled turbo/IC hose off and did the bike tube trick, only a slight hiss coming from below the TB.
6. I believe so, emailed with Eric and my TT chip is programmed for 50# MSD injectors
7. yes
8. no, WBo2 is in its place"

5. Slight hiss = slightly more air thus forcing IAC to close more to compensate. But still should even out once you've started to move at any speed. Make a point of finding the exact source of the hiss. Throttle bodies wear out too.

6. MSD - not for me, too many horror stories. Also, the part number carries all the info you need including impedance.

7 & 8 - how is you PLX wired and grounded?
I have a chip for my wideband which I could never get it to work. Wideband was always too rich regardless of driving habits. Wired to specified pin on ECM and grounded off the ECM chassis. Went back to TT chip, no WB. I use 42# injectors.

injector pulse is normal, just loud. I have mine in exhaust wrap to help shield from heat and keep noise down. You knock sensor is not picking it up so you are good.

how well does it launch? My truck would bog if I just stomped on the pedal, then a second later it would boost nicely. It did tons better if I let it build a couple pounds of boost off the line. Always down shifted manually to 2nd gear if doing a boost launch of any sort and this thing would go, go, go... until the CEL last week. It's back in the barn since I'm working on another truck.

you mentioned a new distributor is on its way. Use Delco parts for your ignition. I'm rooting for that to be your fix.

one other thing, do you have stock chip and injectors? Stock O2? Stock MAP? You get the point. Sometimes you gotta start all over, again.

 

[IGottaSy]

I remember reading something about adjusting the fuel rail height to prevent metal to metal contact the fuel rails are slotted .

This works as long as the orings still do their job. I have read of people using 2 orings per injector but... don't know. I suppose a rubber washer could be used at the fuel rail mounts.

 

[Mephisto]

I would concentrate on these.

"5. pulled turbo/IC hose off and did the bike tube trick, only a slight hiss coming from below the TB.
6. I believe so, emailed with Eric and my TT chip is programmed for 50# MSD injectors
7. yes
8. no, WBo2 is in its place"

5. Slight hiss = slightly more air thus forcing IAC to close more to compensate. But still should even out once you've started to move at any speed. Make a point of finding the exact source of the hiss. Throttle bodies wear out too.

6. MSD - not for me, too many horror stories. Also, the part number carries all the info you need including impedance.

7 & 8 - how is you PLX wired and grounded?
I have a chip for my wideband which I could never get it to work. Wideband was always too rich regardless of driving habits. Wired to specified pin on ECM and grounded off the ECM chassis. Went back to TT chip, no WB. I use 42# injectors.

injector pulse is normal, just loud. I have mine in exhaust wrap to help shield from heat and keep noise down. You knock sensor is not picking it up so you are good.

how well does it launch? My truck would bog if I just stomped on the pedal, then a second later it would boost nicely. It did tons better if I let it build a couple pounds of boost off the line. Always down shifted manually to 2nd gear if doing a boost launch of any sort and this thing would go, go, go... until the CEL last week. It's back in the barn since I'm working on another truck.

you mentioned a new distributor is on its way. Use Delco parts for your ignition. I'm rooting for that to be your fix.

one other thing, do you have stock chip and injectors? Stock O2? Stock MAP? You get the point. Sometimes you gotta start all over, again.

I pulled the throttle body out cleaned all of it, and replaced all the gaskets. It's always had a slight hiss like a pin hole in a bike tube, my Syclone had the same thing. My vacuum level is 18-19 at idle, which I figured is acceptable. I adjusted the throttle stop screw and got the TPS voltage and the lAC counts down to 30, so that's all good there.

I didn't pick these injectors or install them... (that's a story for another time) and I don't have the model number or any of the info on them. I don't have the stock injectors anymore as apparently they were FUBAR from this being a Saudi truck and running leaded gas. The PLX is grounded to the chassis of the ECM. The truck runs fine around town or cruising on the freeway... AFR is right in that 14.7ish wheelhouse. It's just from a stop or when I get above 5psi that the injectors are just dumping fuel in there.

I wish I had all the stock parts to start over... I don't have a stock eprom, the previous owner "couldn't find it" when I bought the truck and I haven't been able to source one on here... All I have is an ATR pitbull chip and a 2-bar.

Honestly, I'm afraid to launch it haha. If it bogs out at 5psi, just trying to get on the freeway... I'd prefer to get that sorted out before going WOT. I'm just afraid of causing some other problem, and having to piss away more time and money on this thing.

I could adjust the fuel rail height which may quiet down the ticking, but I don't think it'll solve the chattering problem. I'm gonna pull the harness and test the impedance of the injectors. I did a lil googling and read that if the injectors are the wrong impedance for the chip, the injector drivers could be damaged thus causing this problem? I'm gonna get to the bottom of this shit though! hahaha. This 27 year old POS is not gonna beat me!

 

[IGottaSy]

Sounds to me the PLX and ECM aren't jiving. You could try to run stock O2 sensor and match that tune on the chip. #7 = 99 is WB off Just to see what it does. Please, someone correct me if this is wrong.

Or perform this song and dance...

https://howtune.com/articles/375-tuning-the-turbotweak-velosyty-chip-on-a-gmc-syclone-typhoon

 

[IGottaSy]

I figured out my CEL issue. Turns out the brown wire was not making good contact. Was throwing code 42. Weird thing though, I could turn ignition key on / off / and restart and it would go away until next key cycle.
how s your sleuthing coming along?

 

[Mephisto]

ok... well it's been a lil while and figured I'd post an update. So reached out to Eric at TurboTweak and he tweaked some fuel settings and sent me another eprom. I popped that in, and the hesitation is gone. Yay! However, the AFR is still dipping down to 10 when I blip the gas at idle, and i'm still getting little random pops/misfires, and this rpm surge when decelerating... oh and the exhaust still smells, not so much rich as it is just potent.

I ordered another WBo2 on amazon just to rule that out, and as suspected, no change. It was also suggested that the cat could be clogged. Took it to a local exhaust shop and had them do a backpressure test. All good there. Literally no backpressure. I pulled the TT chip out, loaded a 50# bin from the old 50# ultimate chip into my ostrich and tried that. At idle the AFR went straight to 10. I drove it around a bit and it ran ok, but whenever I stopped, the AFR went to 10. So i opened TunerPro and messed with the tables a lil bit, and I got the idle to lean out to around 14... but still with the random pops/misfires. Short of the distributor, I've replaced everything... plugs, wires, ICM, cap, rotor, and coil.

So... because I love aggravating myself and because I loathe this truck and working on it. I decided it would be a good idea to pull the valve covers off. Ok first off, eff this truck, eff it right in its filthy 3" tailpipe! Holy hell! What an incredibly unnecessary and difficult pain in the ass that is! Anyway! After pulling half the truck apart to get the valve covers off, I pulled the plugs, and then had to pull the fan shroud, and the fan... so I could crank the motor over by hand and check the valve lash. The driver's side was pretty good, but the intake valve on #6 had a ton of slop, and the #2 and #4 exhaust valves had some as well. So I tightened those up, and put everything back together. I put the TT chip back in since it seemed to run a lil better on that one, and took it for a spin. Definite noticeable difference, so it wasn't a total waste of time. It feels a lil smoother when cruising around and a lil more responsive. But I'll be damned if it's still not randomly popping/misfiring at idle and surging at deceleration. I'm thinking it's gotta be something with these injectors, maybe they're not flow matched correctly or something just isn't jiving with the TTchip or the old bins from the 50# ultimate.

If it's not the injectors, that really only leaves the ECM and the PLX... outside of that, the only fix is a gas can and matches. I'm just over it, and so sick of screwing with this thing. It's so bad I lashed out at a guy at the gas station yesterday, when he told me these trucks were badass! hahaha

 

[IGottaSy]

Poor guy. Shoulda told him it was for sale. Like I said before, I've read gloomy stories about the 50# injectors. At least you learned something new. Clearly, not enough to make you forget about fire. I need to send TT my chip as well. I just have been enjoying romping on this thing around town with no issues but a little hard start when at operating temps. I am probably off a degree or two with the timing. Truck runs strong for a 123K mile motor. Chip is for 91 and no wideband. I get no knock cause I fill up with either 93 octane or 93 plus a couple gallons of E85 when I feel like driving to the only gas station that sells it. Keep messing with it but leave the 3" tail pipe alone.
shoulda wrapped the injector fuel rail with some thin exhaust wrap to keep cool while it was stripped.

 

[Mephisto]

Poor guy. Shoulda told him it was for sale.

haha I wasn't too bad to him. He just caught me at the wrong time and came up all cheery and said "oh I remember these! These things are badass!" and I just gave him a death glare and said all snarky "That's right! Baddest trucks ever made until you own one, and the piece of shit is constantly broken! Hence, the license plate... Have a good one!" and got outta there. Haha the guy must have thought I was a total dick, but he was just an innocent man in the wrong place at the wrong time haha.

I gotta try to go get this thing smogged again... my registration expired in April, and once we hit June all bets are off. The "super busy" cops here will pull you over in a second for it, on the off chance they're gonna bust you for something else. I really don't wanna deal with those guys and their empty threats of impounding the truck and suspending my license. I'll just dump more 101oct in it, and do some WOT blasts to get everything good n hot before I go in there, and hope for the best. I don't think I had the truck hot enough last time.

Even if it passes smog I still need to sort out why it's idling like crap and why around town driving sucks. I'm convinced it's the injectors that are crap. But I'll try going back to the stock o2, and swapping the ECM before I buy new injectors. If none of that works, then I quit. We'll just close this thread and call it a Typhoon cold case.

 

[IGottaSy]

Get running right and sell the thing to get the new Sucklone coming out.

https://youtu.be/_vm73XpT5D8

 

[Mephisto]

Hahaha never! That thing is a travesty! Even if they had put the turbo ATS-v motor in there and made it AWD, it's still way too big and clunky. I love how small our trucks are... but then again, I'm not over 6ft tall and pushing 280lbs or more... So getting in and out of my Ty isn't a struggle.

If/when I sell my Typhoon, I'm buying a 67 Nova SS, like I should've done instead of buying this Typhoon. That's always been my dream car (besides the 69 Charger, damn you dukes of hazzard!). I can climb into that engine bay to wrench on it, and don't have to take half of the car apart just to get the valve covers off! It's just a matter of finding one that's not totally fubar, or restored with a bunch of dated gaudy crap all over it.