2Fast 2Low

I have an 86 Camaro MAF TPI on top of a 93 Chevrolet TBI with roller cam and lifters. The engine has been together for about a year, but still not running correctly. Right now, the engine is having alot of trouble idling when the MAF sensor is connected. however with the maf sensor disconnected it does not rev very well, and has intake backfires (sounds like it is coming from the air filter) I have rewired all the relays, because i had some power problems, I have put a test light to the maf plug but have comeout even more confused. Fuel Pressure is good, and I have found all the vacuum lines and connected them, i think. On the drivers side, there is supposed to be a pcv valve, but i just have a breather there right now, and on the passenger side valve cover, I have a hose run to the throttle body air in. I just want to get this running, and do not wanna give up like sooo many people have.

Here is my vacuum system currently. I have a line run to the brake booster from the intake manifold also.

birdtojag

iTrader: (1)

Sounds like you need to make sure you have all your vacuum lines hooked up properly. I would get rid of the breather and put in the PCV and route everything like it's supposed to be. If the problem goes away, then you found your issue. If not, keep looking for anything else that could be wrong.

regal301

its a maf car with a slightly different motor, i had this happen to the first motor i put in my car,and when i changed my battery ,it needs to relearn the fuel table and its most likely backfiring out of the intake because its lean.BUT ......YOU NEED PCV AND THE BREATHER HOSES HOOKED UP CORRECTLY AND AIR FILTER ON SO IT CAN PROPERLY LEARN.the mass air flow cars from my experence are slow learners.you will need to finish it and take it for a drive.also make sure the tps voltage is set right.and this is assuming your maf is ok and timing is set etc......

2Fast 2Low

Thank you for your input, both of you. I have been really busy with a new job and have not had time to reply. When i get a chance, i will fix the breather situation, and try it again. Thanks again. I will pick this back up hopefully this week.

Chevy86 IROC-Z

iTrader: (17)

Do you know another tpi owner. If you do, switch ECm's just to see if the computer is bad. Also try someone elses MAF sensor. Definately reconnect the PCV back to the intake manifold (nipple next to cold start injector). This may be off the subject but I need a little help. If your willing to help, let me know because I have an issue about my vac line. I'll understand if you dont have time. One more thing. You may need to test the EGR valve sensor ( little wire that sticks out of the valve itself. pic below)

Chevy86 IROC-Z

iTrader: (17)

wait a minute, you have a TBI............. 1993...... Is the engine a VORTEC (heads and block). My brother n law dropped a vortec in his 87 IROC Z and his ECM couldnt run the motor right. It would fire up and revved like if the devil was being ressurected. But once he drove it, it would begin to stutter at around 25 MPH. so the mech says that he may need to mod to a MAP system. VORTECS can be a headache,,,, if you have one with a TPI setup.

regal301

93 is NOT a vortec, 96 up IS a vortec and wouldent have been a direct bolt up on the intake.and a tpi will run a vortec motor with a maf or map sensor ecm. I HAVE RUN THOSE MOTORS IN MY CAR WITH THE MAF AND MAP ECM'S WITH A STOCK PROM AND THEY RAN FINE.i have a vortec in my car now.

Chevy86 IROC-Z

iTrader: (17)

Hold on there! Y are you so mad for. Whats with the caps Regal. Im trying to help someone else out and your getting ****. There is no need to yell at me dog. You need to chill out dog. No need for . I think your caps are . Throwing caps wont get you no where buddy. Plus I never said that my Bro n law had a TPI on a vortec. He's got a Holley Stealth Ram EFI kit on his vortec engine. . Besides it aint even your thread foo.

regal301

no im not mad or anything i just wanted to be clear.sorry if i come off as mad.i am just straight to the point with no b.s............ its a new england thing.

a stealth ram is a tpi and should still run a vortec.its just a different runner length.

the vortec 350 ( l31 ) is as close to a l98 as you can get.(from a late model chevy )

Chevy86 IROC-Z

iTrader: (17)

No problem. . I was like,,,who,,,me,,,,,what/ Nah bro it's cool. Yeah, my bro n law got a vortec and the mechanic is telling him that he needs to convert to a MAP so that his ECM can operate properly. Personally, I think the mech is pulling his chain you know, trying to squeeze more money out of my bro's wallet. I myself got a L98 from a junkyard for $75 dollars. check out my homepage. I got the block there in my album. Talk to you later regal.

2Fast 2Low

Man I feel like an A$$ with my lack of attentiveness to this thread. I am really not this lame usually, sorry, and thanks for dealing with me. I have not been throwing alot of money at the engine, but will spend the money for a pcv this week. The engine seems to have horrible shakes at less than one thousand rpms, is this still something consistent with the pcv and fuel tables. I will do that pcv and brake out the camera for video this week or weekend.
Thanks everyone

Chevy86 IROC-Z

iTrader: (17)

If your engine shakes while under 1000 RPM's It could be a matter of things. The ones off the top of my head are vacuum leak, lack of fuel to the injectors, re-adjustment of the throttle position sensor, bad oxygen sensor, bad fuel pressure regulator, re-adjust distributor, bad spark plugs, bad spark plug wires, bad mass air flow sensor. The best suggestion is you can call Autozone in your area and see if they still do free computer analysis (to read trouble codes). Then youll be directed in a more accurate direction of troubleshooting methods. If you own a Haynes camaro repair manual for our 3rd Gen camaro's, it shows you how to insert a paper clip into the little box under your steering wheel. Once the clip is inserted, turn on the key and your check engine light flashes. count the flashes and match it with the corresponding trouble code definition. The trouble codes are stored within the ECM. This is the cheapest way for you to verify what kind of issues your sensors are picking up. To make it easier for you, here is the instructions on how to pull the trouble codes and how to get em. http://www.iroczone.com/specs/TroubleCodes.htm

2Fast 2Low

I have an OBDII aldl cable, so I can pull the codes. Thank you for the starting point though.
vacuum leak-Probable
lack of fuel to the injectors-Put a pressure gauge on it and got 40 while running
re-adjustment of the throttle position sensor-Have gotten in the ball park
bad oxygen sensor- am not getting any codes, and its new
bad fuel pressure regulator-maybe?
bad mass air flow sensor- Possible although have replaced twice

I will look these over this weekend.

Chevy86 IROC-Z

iTrader: (17)

z28 TPI

Couple of quick questions. I know there was 2 different intake mainfolds on the camaro the first range from 85 to 86 the second range from 87 and on. Reason why I ask this is the heads on the sbc 87 blocks and above are different angles which cause vacuum leaks when you try to put an 86 intake on them. The quickest way to tell is have a spray bottle with very little soap and a lot of water. When the engine is at idle spray the base intake mainfold along the edge of the head and see if you have a leak there either should be bubbles or in this case the engine might stuggle with the suction of water. Easy way to tell if you have a bad fuel pressure regulator is to take the vacuum line off the intake mainfold and put the key to the on position. If this is the first time in awhile that you turn the key the fuel pump should run and fill the lines with pressure if the fpr is bad there will be fuel coming out of the vacuum line. Sounds odd that 2 maf sensors would go bad but it could happen. When you unplug the maf the engine will idle but not rev, when you plug the maf in it doesn't idle, does it run? It also could be the timing. Is the dist in the right place? How's the timing chain how many miles on it? It does sound like a vacuum issue though. I know that on the 87 and up upper intake mainfolds there is a tapped boss for the map sensor, but you said you have 86 intake right. If you do have an 86 or 85 intake the casting numbers are 14081005 the 87 and up intakes had casting number 18483572 maybe this could also help you in figuring out exactly which one you have.

I hope that this can help you in some way let us know what happens bro.

2Fast 2Low

Thanks for more input, I have decided to replace my wiring harness with a painless wiring harness that i am getting for $150. Should help clear up any possible electrical issues that I could be having.