Well, dealership thought it was vapor lock. Mechanic pulled a fuel line during the no start condition and said the gas was so hot it was instantly vaporizing in the can!
So I heat shielded my fuel lines back by the number 7 header tube and built a shield around the #7 tube. Still no start.
Once again, ZZ4TPI starts fine cold, won't start after it gets hot, just cranks. Good fuel pressure on the rail. Replaced or swapped following:
distributor
ignition module
ecm
coil
cap/rotor/
battery
alternator
good wires and plugs
adj fpr.
Could the injectors be heating up and not firing properly?
In case you don't remember, sometimes I can advance the timing way forward at the distributor and the car will start. Then I can back it off to normal and car runs fine.
Yes, all timing has been set with the ecm disconnected. I've also disconnected the MSD 6AL to be sure it wasn't that, it wasnt.
tks
p.s. GMTech, whats up with sethirdgen?

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Rob, I have followed this problem from the get go, and frankly, I'm baffled. I was w/ John, I didn't think it was Vapor lock, because 45 psi should be enough to prevent it. Remember, the cooling system can get up to 260* before it starts boiling, and thats w/ a 15 psi radiator cap. But I will keep searching for an answer.

Still coming up this weekend?

As for the message board, its being moved to another (supposedly faster) server, and should be back up today. Talk to ya then.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

I don't know if you've tried this, but at this point, it sure can't hurt...
Have you tried playing 'mind-games' with the ECM. Try swapping in resistors for the IAT and CTS to make it think it is colder than it is. Yeah it would be trying to start rich, but at least you'd know it wasn't something screwed up in the programming.
You still have MAF on it too right? Is it possible that the MAF gets heat soaked and doesn't register any air at the low flows of start-up, thereby screwing you up.
I know, these are reaches, but at this point can it hurt?
...ed

 

Ed, sorry I forgot to mention its a MAP car.
--
A couple thoughts I've had.
Could the knock sensor be going bad and registering excessive knock counts and retarding timing while starting? I doubt this because I've heard the ignition module handles timing until the car starts, then the ecm takes over. So the knock sensor doesn't come into play until the computer calls the timing shots.
--
Something with the injectors? After they heat up they stop working properly? If I do get it to start hot the car runs fine after that and I can retard the timing while its running. The GM Tech One showed a good air fuel, maybe a tad rich (#24 injectors most likely) so I doubt it's the injectors.
--
Could the MAP sensor be heating up? Thats about the only thing I havent changed.


------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Rob, you and GMTech have obviously been workign on this problem for a while so I won't suggest any specific part that needs to be replaced. However.....

I think you need to start ELIMINATING THINGS IT CAN'T BE. First off, I'd nail down for absolute certain whether it's fuel or spark. Disconnect the fuel pump (temporarily!) while you are experiencing this problem. Then spray a shot of staring fluid into the intake plenum. Crank it. Does it fire momentarily and then shut down? If so, you've got a fuel problem. If not, it's spark related. So you're 50% of the way to fixing the problem!

I agree that vapor lock is unlikely, despite your mechanic's findings. EFI line pressures are high engough to prevent this and the return line-type fuel pressure regulator system allows a CONSTANT cycling of the fuel back to the tank and a fresh supply of COOL fuel to be drawn into the fuel line going to the engine. So I would think it's unlikely.

My second suggestion would be to beg borrow or steal a scan tool. Can't tell CRAP without seeing what the computer sees. And you end up "throwing parts at it" for weeks and never solving the problem. These little things are invaluable for tracing weird gremlins like this.

 

Unfortunately the only scan tool we have been able to get to talk with this crappy chip from Street and Performance is a GM Tech scanner. I tried Diacom and I bought an Autoxray, no dice. The autoxray did hook up for about 5 seconds one time. Weird.
I'm heading to a friends house this weekend and I'm pretty sure he has a GM Tech scanner
I'll try the starting fluid, a $2 can is cheaper than some of the parts I've been buying!

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Placing bets on the ECM?

 

Joel brings up a good point. If your scan tool can't talk to the ECM that might indicate problems right there. Diacom ALWAYS works on the cars I have used it on (including many 3rd gens) That is IF you use the correct plug adapter- they supply 2. One is the "standard" one and the other is a "TPI" one. And I have found that many TPI engines you use the STANDARD plug ANYWAY- the TPI specific one doesn't work on some TPI cars, believe it or not. Other than that, Diacom never just "won't work." Never.

Anyways....... So you get flaky results trying to hook up a scan tool. And you get flaky hot start behavior. Hmmmmmmm....... They could be related. Bad ground? Plug not plugged all the way in on the back of the ECM? Something remarkably simple like that?

 

Sorry, third ECM in the car. Thought the first one was bad so I bought a reman unit. Did the same thing so I swapped a known good ECM from my 92 Z28 convt (both are 92 MAP systems) same thing. The diacom and autoxray hooked up with the 92 Z28 ecm and the remanufcatured unit while it was in the 92 convt. Would not hook up once in the ZZ4TPI car. Another friend with a ZZ4TPI chip from S&P reports he cannot get a scanner to hook up on his car.
Like I've been telling you, this one is baffling.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Wait a sec, the chip tested good in another car, but not in yours? Check the ALDL wiring! Sounds like a wire is bad in there (may not be the start problem, but probably contributing somewhere!) Also check grounds, just a little noise in the ground can cause ECM hell.
Good luck


------------------
Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
1987 Pontiac Trans AM (GTA?) 350 or is it a 305?! TPI
SLP 1 3/4" headers, 3" cat back (stock cat
MSD ignition.
MSD Blaster SS coil.
3.73 Rear end gears
Accell 8.8 Wires
Bosh +4 Spark Plugs (Don't know if they really help but hell!)
Holley AFPR
Race Built Automatic trans ('vette servo, shift kit, tightly packed clutches)--just needs titanium gears now!
Newly gutted cat (the car gutted it's own cat!)
Hypertech Chip (Just found out I had it! :eek
More soon when funds are avail...

 

As many of you know I too have had a hot start problem with exactly the same problems as Rob, and I have eliminated everything that Rob has. So now the only thing left for me to do is to figure out if maybe the injectors are not atomizing the fuel very well for hot starts causing the engine to be flooded out.
My injectors are stock 19 lbs from 1985 and have never been rebuilt/cleaned so I am wondering if maybe they could be the cause?

------------------
'84Z28/'92 305TPI
'92 complete rear suspension/PBR disc/Posi/3:42
Light weight 34.5mm stabilizer bar in front ($10 from wrecking yard)/
"wonder Bar" ($5 from wrecking yard)
23mm sta. bar in rear
Rear RS Springs (slightly softer than my Z28)
comp cam, flowmaster
TB coolantbypass/shutoff valve to heater core
powersteering cooler lines (liberated from another wrecked car of course)
MAT relocated
Ram-Air(home-made) gutted air-box
IROC ground effects/wheels GY245/50's
700R4 superior shift kit/ corvette servo(excellent shift kit btw)
home-made strut tower brace (cost $6)

Rebuilt engine and transplanted it myself.

Love this engine!

freshly painted OCT. 2000 Teal with two white stripes on the hood and deck lid

LOW performance people should drive low performance vehicles!

 

Rob,

If you suspect the detonation sensor and excessive knock counts, bypass the EST for starting (it should be bypasses anyway, but you have a "custom" PROM that might not be compliant.

The idea of half-splitting the problem is a good one, except you might want to use fuel in a hand pump instead of starting fluid on a hot engine.

------------------
Later,
Vader
------------------
"What a Day..."
Adobe Acrobat Reader

 

84IROC, I'd definately get your injectors cleaned and checked. Think of how many times they have pulsed over the years.
Vader, If I remember (I've done so much troubleshooting I've forgotten some of the stuff I've done!)I did unplug the timing control from the computer during hot start and it did the same thing.
I'm leaning towards the ground thing, especially since my battery is in the trunk. My neg lead goes to the back of the tranny, were the bolt goes into the engine block. I then have two grounds running from the heads to the firewall. My ECM ground is directly connected to one of those grounds. I think I'm gonna pull the whole negative cable today and reroute it, see what I can do to find a better ground spot maybe.

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Well, after spending all day with GM Tech (BTripp) and John Millican we isolated it to a fuel problem Apparently the injectors are not pulsing sometimes. Little starter fluid and it fires and brings the injectors to life. We did during a no start, pull the number 2 injector and the car would start, got that to happen 3 times. We think perhaps one injector is grounding out and dragging the voltage down with it. GM Tech can explain much better than I. I am gonna pull the injectors and have them tested.
Special thanks to Bernard and John for taking their whole Saturday to work on my car. Guys, Bernard and John know there shiitt about TPI cars! And Bernard has the best toys in his tool box you've ever seen!
It's not fixed but in one day with these guys, I learned more and the problem is more isolated than after 2 weeks at my Chevy dealership.
OH, my AUTOXRAY scanner is hooking up about 95% of the time now. Pales in comparision to the GM Tech 2!
------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

[This message has been edited by Rob P (edited April 28, 2001).]

 

Glad to see you have it narrowed down!

I was going to reccomend cycling the key several times to circulate cool fuel to the injectors in case it is an injector problem. You could also connect power to ALDL pin "G" for a short time to do the same thing. I would think the fuel running through the rail would cool the injectors a but and help the situation.

------------------
Working on:
'84 Z28 LG4 305 with 200,000 original miles!
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350 (ZZ430)
using primarily GMPP parts.
Short block sitting on a stand. (Man, those Fast-Burn heads sitting on it look good!)

Starting to look like the Kicker poster child!

ASE Certified Master Tech

 

After discussing it with Bernard and John, 45psi should be enough pressure to keep the fuel liquified (15psi keeps water to 260deg F before boiling).
Also, the car would hold pressure for days, and now all of a sudden the fuel pressure is bleeding off fast, making me believe perhaps #2 injector has given up completely on the ride home. From Savannah Ga to Jax Fl (2hrs) it felt like the car was on 6 or 7 cylinders, top speed 65mph, but sometimes it would smooth out and feel normal. I eventually made it home. With everything we learned and the rail not holding pressure anymore, I'm leaning towards the injectors.
Of course I've leaned a lot of directions before with this problem

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Rob, thanks for the flattery, but save it for when its fixed!

But like Rob said, my theory is that since this is a batch fire system, and electricity ALWAYS seeks the path to ground w/ least resistance, that one injector may be getting hot, and the coil inside is becoming shorted, its stealing amperage from the other injectors, causing them to not start. What I don't know, is: There are two banks of injectors, left and right. Each bank has its own pin at the ECM, BUT, the Service manual shows them tied together inside the ECM, so I assume that if one injector is shorted, its pulling the other seven down.

Several reasons I beleive in my theory:

First, the cars runs rich when it does run. Do all cylinders run rich? I don't think so. Last time Rob did a tune-up, the right bank injectors were black, but the left bank were good. Well, the #2 cylinder is on the right bank.

It seems everytime it won't start, we can unplug the #2 injector connector, and it will start. Happened three times. Its either true, or major coincidence.

I did a "snapshot" of the no-start, and graphed it out, and after four failed attempts to start the car, the computer shut the injectors off, which tells me the "current limiting" feature of the injector driver may have kicked in to save the computer, wich would also point to a shorted injector.

Plus, its about the only thing that hasn't been replaced w/ a known good part.

I have my fingers crossed....

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

[This message has been edited by GMTech (edited April 29, 2001).]

 

Heres a little more info.
Pulled the #1 plug, pretty clean. Pulled #2 thru #8, all sooty black. I don't know how the car ran two hours home! I believe if I didn't have the MSD box there would have been no way (but lets not get started on that). I checked the cap, rotor and all was fine, clean, good working order.
I've cleaned all plugs and reinstalled but will fire it up after I pull the injectors and have them tested.


------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Yet some more info:

Most of the plugs were black (overly rich condition). The ride home, Rob mentioned his Fuel Trim was at 148 (lean) so the computer was seeing a lean condition and dumping fuel. The "suspect" injector is on the right bank, but the O2 sensor is on the left bank. If the "suspect" injector is indeed stealing amprage from the other 7, then the other 7 injectors would be running lean, including the 4 on the left bank, where the O2 sensor is, so it reports back to the ECM that the air/fuel is lean, so it dumps fuel. I'm confident you will find an injector problem. Theres too much supporting evedince.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
--&gt;14.97 @ 94.9 MPH&lt;--

'97 Bonneville SSE

 

That kinda reminds me of the nightmare I had with a 95 vortec 6 blazer. It all came down to using the plastic clips that came with the replacement fuel pump blowing off pressure (around 57psi) and thats not quite enough for the vortecs.

This was found after 2 computers, a whole new injector spider/regulator and dropping the tank 3 times. After calling the fuel pump manufacturer and 'reamin' them they said 'ohh yeah, don't use the clamps provided with the pump for vortecs'....

 

Well, had the injectors tested. Nothing with #2 as I suspected. It has to be hot to act up. However, #3 was not closing properly after being fired, so it was dumping fuel all the time. Probably helping with the over rich condition.
My SVOs will be here tomorrow. Hopefully I got the correct ones, not the inch short ones or Summit will be overnighting me the correct ones!


------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Well today I went to Roys Diesel and Fuel injection to pick up my injectors. I asked him how much it was for the work he performed, just tested them, nothing else. $123! I was expecting like $40 or $50. Rick at Cruzin performance tested and flow matched them for $50! I laughed and told him to keep the damn things! I found out what I wanted to know and I wouldn't have trusted any of those injectors (if one or two were bad, when would the rest go bad?)
So Summit delivered the new SVO injectors, correct size and on time! They installed great, tighter than the stock GM ones.
Fired the car up and everything seems okay. I do have a dead solid miss, I'm pretty sure I still have a dirty plug or a loose wire. I gotta clean the number 1 plug, it was the only one I didn't clean. I got through 3 or 4 hot restarts with no problem. Fired right up, starts faster then before with less cranking.
So, lets see, $90 for new ECM, $230 @ 2 weeks at the dealership for them to tell me my car was vapor locked, and about 40 hours of my time troubleshooting the car and she still wouldn't run properly. I take it to Bernard for 8 hours, two tanks of gas, tank up, tank back, $230 for SVO injectors and she seems to be fixed.


------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

After I got everthing back together I had a dead solid miss. I eventually found two bad plug wires. Not sure why, they are only a few months old, I think the heat from the headers is doing a number on several of the wires. So new plugs (I wire wheeled them to clean them), new wires and some heat shields to protect the wires.
The SVO's did cure the hot, no start, she starts everytime now, YES! Once again, thanks to GM Tech, aka Bernard Tripp and John Millican for taking an entire Saturday to help me out.
p.s. You won't find those crappy injectors on the forsale board!

------------------
Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!