HELP!!!

I just put a new 290hp gm crate motor, when I try to start the car, i have to put my foot through the floor to get the engine to stay running. I've been told everything from (poor fuel pressure, to bad Distributor, to possibly a bad Coolant temp sensor)! BY THE WAY Should the coolant temp sensor be on the far right or should the cold start switch be on the far right side?) If they were place in the wrong port could that cause serious problems? Also, I should mention that I had a custom prom burned by TPIS with the below listed parameters! Any suggestions! PLEASE!!


1. Engine size 350 TPI CHANGED ENGINE TO (GM PERFORMANCE ENGINE PART #12499529)

2. Injector Size/Brand 26LB ACCEL
3. e.g.r. DELETED
4. BBK adjustable fuel pressure regulator
5. Fuel pump 255 LBS PER HOUR
6. 3 WIRE GM 02 SENSOR
7. A.I.R. PUMP HAS BEEN DELETED
8. WITH A/C (Sanden 508 Compressor)
9. March Performance underdrive pulley set part# MCH-4130
10. K&N air filter
11. Distributor has been switched from 1985 HEI to MSD Ignition 8366 Pro-Billet Magnetic Pickup, Electronic Advance & 6AL Ignition Box
12. Throttle Body is PROFFESIONAL PRODUCTS 52MM
13. Stock Intake Manifold & RUNNERS (NOT PORTED)
14. TPI Plenum has been (MILDLY MODIFIED PORTED OUT)
18. Thermostat Temp 180 DEGREES
19. Exhaust System 68441 Headman Headers Primary Tube Diameter (in) 1 5/8 in. with dual PYPES cats 2 1/2 pipes all the back
20. Transmission: 7004R
21. Torque Converter is a 2800 STALL (WAY OVERKILL BUT I MAY EVENTUALLY BE PUTTING A DIFFERENT ENGINE IN )
22. Stock Rear gear ratio 2.73

23. New Tire Size is 275/40 ZR17

 

The stock injectors for the 85 should be 24 pound. I am using the new Accel 24 lbs injectors and am generating a lot more HP that your engine.

We need more information to help......list of your mods are okay.....tells us WHAT is happening when it starts up. Is idle up and down? Any codes being thrown by the computer?

Check exhaust.......is the inside of the pipe very black from running too rich?

Have you checked fuel pressure??

 

When I can get the car to start up, it sounds like it is girgling, when you drive it, it seems like it is running at half power like it might be only using 4-6 cylinders, it backfires and moisture is coming out of the tail pipes (black in color)! When you come to a stop, like at a red light you have to rev it up to keep it running. I changed the plugs, I put in a new coolant sensor and a fuel pump relay! Keep in mind, I am Mechanically inclined, but not a Mechanic, and I do not own all the necessary and essential tools that I should. Also the PSI is set at around 50 psi, because at 39-42 psi it would no run at all!

 

Black smoke coming out of the exhaust means it running too rich. What is the fuel pressure set at? Are you getting any codes?

 

PSI is set at around 50 psi, because at 39-42 psi it would no run at all!
Engine light is on but I don't have the tools to scan for codes!

 

You need to get that thing scanned. The 26Lb. injector thing and the rest may need to be re-tuned, as many intial tunes are not correct. I'm sure I'll be sending & re-sending the chip this spring/summer, as I've had to do before. One day with more time I'll tackle the DIY tuning. But it may be something that is more than just fuel adjustment at the FPR & such.

 

Also, pulling codes from the ALDL is not always accurate - I've had codes thrown from not re-connecting sensors/a sensor, that had nothing to do with what I didn't re-connect. Once when my battery went bad, I had all kinds of codes - that really opened my eyes. Keep in mind the ECM for the 85 is specific for that year, and unless you have parameters set in your PROM when tuned, you're not going to get as much info as the OBD II guys. It is slow and primitive. For example, if scanned, your stock ECM may not show Block learn or integrator, but I asked my tuner to put those parameters in the prom, and now I can see them with my archaic auto Xray scanner. You will be able to see O2 readings, and that should help. Maybe other 85 owners had some different experiences they can share to help you.

 

Thanks for all the help and advise so far guys. I'm still not exactly sure where to go from here other than to get it scanned first!

 

Regarding the temp sensors. There are 4 temp sensors or switches on your car. The radiator fan switch is in the passengerside head. The sensor for the gauge is in the driverside head. The sensor for the ECM is on the front of the intake manifold. Next to it is the switch for the cold start valve.

 

Stock on an 85 350 is 22LB @ 43.5psi but tuneing around the 26's might be abit of a problem.

 

Man, that sounds very similar to the problem I had several years back. I also had the MSD 6AL. One day on my way back from the beach, mine just shut off while driving. Then, to keep it running, I had to keep it revved and even then it wouldn't run great and backfire and buck. After 3 tows, 2 shops, new fuel pump, filter, and lots more over many months, I finally removed all the MSD stuff and went back to stock distributor, coil, etc and it hasn't had that problem since. May not be exactly the problem you are having, but boy did that bring back some dark memories for me

As far as the injectors, I heard over and over that stock '85 were 24lb so I put in new FMS 24# injectors several years ago. Now I am hearing about 50/50 people saying '85 injectors are either 22# or 24#. I am starting to believe they are 22# stock because I'm having a hell of a time with mine running rich, even though I suspected the same before replacing the injectors.

 

All you need is a paper clip to jump terminals A and B on the ALDL connector and count the flashing SES light.
Read these

http://www.corvettephotographs.com/c4vettes/codes.htm


http://members.shaw.ca/corvette86/No...it%20Check.pdf

 

OK,

Since I work at a chevy Dealership, I was able to borrow a Tech 1. Took it home, scanned the beast and heres what I got with the car not running but with the key turned to the on position (Obviously). I guess you can't scan the car with it off!! Can some here help me make heads or tales of this? The Techs where I work do not want any part of this car at all and offer no help what so ever!

(No trouble codes at all)
TORQUE CONVERTER CLUTCH OFF
IDLE AIR CONTROL 144
PARK / NEUTRAL P-N--
OPEN LOOP
RICH LEAN FLAG LEAN
O2 SENSOR 453mv
INJECTOR PULSE WIDTH 0.0 M.SEC
FUEL INTERGRATOR 128
BLOCK LEARN 128
TPS .38 VOLTS
MAF 3.0 g/s
SPARK ADVANCE 0 DEGREES
DIAG STATE (10K)
PROM ID 0
4TH GEAR DELAY ON
3 GEAR SWITCH YES
BACK UP FUEL & SPARK MODE ACTIVE

 

Have you checked the ign. timing and advance curve with a timing light?, the ecm controls the timing based on sensor info. I'm not sure how the MSD would fit into this. The other points I see from your scan data is that your tps needs to be set at .54 volts after the throttle body has been set for base idle, the other thing I saw was it is running in a limp mode? I use a snap on scanner and you can manually put it in limp mode for diag. purposes, but a tech 1 may show it as actively running that in their pid list. From your description it sounds like a possible timing issue.

 

I just picked up an 85 with a fresh ZZ4 Motor. It was a project gone bad for the last owner he was never able to make it run right and never drove it. Mine had some of the same issues as yours. One of the problems was that when they pulled the original Engine they ripped out most of the Ground Wires. There was some behind the Distributor and a Bare one on the Drivers side not hooked up. Sounds like You might have larger Injectors than needed and more Fuel Pressure to. If you have a Stock sized Throdle Body You might try that to. If there is a performance tunner nearby it will be money well spent these Cars are real simple by modern tech.

 

The 24lb FMS were kown to flow more then 24, Thats why a lot of guys liked them.

 

Hey Brozne85

I drove 100mph home last night and tried moving the distributor around and that seamed to help with the stalling a bit! I think your on the right path but I just can't seem to find the exact location (for the dist. that is)!!!

Gale, I tend to agree with you and jmrl98 about the injectors! I don't know what I was thinking when I bought those 26ld'ers. Now I have 2 COMPLETE, less that 1 year old sets of Accels that I don't know what I going to do with!

This car is driving me Frickin' Insane! This has been a 2 year build. I mean just about everything under the hood and on the car is Brand New! The car is definately not a show car but I bought it for 2 G's and have over 12 g's in it. But If ever get it running it will be exactly what I wanted

 

By the way, if anyone is looking for any parts at all, I still have a lot of the parts that came out of the car except the Intake Manifold and a few other parts. I have a BRAND New EGR Valve for an 85 if anybody's interested and All Of The pulleys!

 

Call FIC maybe they will work a deal with you on your old injectors

 

May I suggest you are swatting at flies with a baseball bat. You have made multiple changes to a car with little if any idea how they all fit together. Strongly suggest you go back to basics, read what Agent 86 said, pull codes for a direction. First you need to set timing and TPS by the book. All else being equal your installed injectors may not be the best but the car should run. Last, I can understand why the Techs don't want to touch this thing, it doesn't fit in any of their training and experience. Did you actually get it to 100 MPH?