Hi everyone im new here and love reading the forum. Heres the problem i just bought an 89 iroc 305 tpi when i first saw the car it would not start if all 8 fuel injectors were plugged in. If you unplugged #7 the car would start and run pretty darn good. If you started the car with #7 unplugged then plugged it in, the car would run rough and stall. So in theroy it would seem that the#7 fuel injector was no good. I trailer the car home and i change all 8 fuel injectors and start the car it started but was so load i thought it was going to blow up (i put the rails on the wrong side) swapped the rales to the proper sides and the car started and ran but ran rough. Sounded like it had a missfire (could feel the engine shake and it has a decent sized exhauzt leak and you could hear the put-put. So i change the plugs and wires. No change still not running right. When i start the car it idles high then comes down(dont know how high it idles the tach is broken) when driving it doesnt feel like its losing powder it moves when you give it gas. It does however seem to be idleing high like i dont have to touch the gas and im rolling 10-15mph. Ihave driven the car about 80miles and its just running rough it hasnt stalled but it smells bad (could be the exhaust its been welded a thousand times) i have done the following to the car
8 new bosh ll injectors (southbay)
Plugs+wires
Oil sending unit
Fuel filter
Changed the fuel lines from the fuel
Couple vacuum lines
Change the fuel lines from the fuel

 

Hi everyone im new here and love reading the forum. Heres the problem i just bought an 89 iroc 305 tpi when i first saw the car it would not start if all 8 fuel injectors were plugged in. If you unplugged #7 the car would start and run pretty darn good. If you started the car with #7 unplugged then plugged it in, the car would run rough and stall. So in theroy it would seem that the#7 fuel injector was no good. I trailer the car home and i change all 8 fuel injectors and start the car it started but was so load i thought it was going to blow up (i put the rails on the wrong side) swapped the rales to the proper sides and the car started and ran but ran rough. Sounded like it had a missfire (could feel the engine shake and it has a decent sized exhauzt leak and you could hear the put-put. So i change the plugs and wires. No change still not running right. When i start the car it idles high then comes down(dont know how high it idles the tach is broken) when driving it doesnt feel like its losing powder it moves when you give it gas. It does however seem to be idling high like i dont have to touch the gas and im rolling 10-15mph. Ihave driven the car about 80miles and its just running rough it hasnt stalled but it smells bad (could be the exhaust its been welded a thousand times) i have done the following to the car
8 new bosh ll injectors (southbay)
Plugs+wires
Oil sending unit
Fuel filter
Changed the metal fuel lines from the fuel rail (where the injectors go) with rubber hose
Couple vacuum lines

Im lost and need help it did throw a code 43 one time when i was on the highway but i think it has nothing to do with this situation and this situation having everything to do with the code coming on. Please help thanks

 

Welcome!
Start here and do a lot of searching...there is TONS of info and knowledgeable members on here.
https://www.thirdgen.org/newdesign/tech/tpimod2.shtml
Good luck!

-Bob

 

Thanks i didnt touch any idel screw only things were the throttel body the rales and rack is it possible the plenum gaskets could be mixed up due to the fact i had them onthe wrong side of the car? Could that cause the car tlrun rough i checked for vacuum leaks with carb cleaner and didnt find anything

 

I think I would do the IAC reset. If you do a search on this forum you should be able to find the info with the proper way to do this. The IAC is the Idle Air Control and it is located in the bottom of the throttle body. You should take it out and clean the tip of the IAC and the air passage in the TB before you do the reset.

 

I just reset the iac when i plugged the iac turned on the car and the car was running rough and stalledthere was no even idel at all i still turned it down some and the tps was off alittle i set that its running a little better but the engine studders at idel it is fine when driving no power loss come to a light and the whole car is shaking and you can hear the engine kind of bog down the idel up bog down idel up im lost and dont know what to do next

 

Check your fuel pressure. What type of hose did you use when you replaced those hard lines? Double check all the routing and condition of the vacuum hoses. If it sat for a while the gas in there could be garbage as well.

 

The two fueling that are on the front of the fuel rack (where the injectors go) were never coming off and looked bad so I cut them and replaced with high pressure rubber hose. The car runs great when your driving no loss of power but you come to a stop and it idels like crap kind of surges then you move and it's fine it doesn't stall I'm not sure if the gaskets in the plenumem are right I can see some of the gasket sticking up on the top of the throttle body I sprayed carb cleaner and couldn't find a leak but if the gasket isn't sitting right in the rales in not sure if that could cause the problem that's pretty much the only thing I have ripped apart to replace the injectors

 

So when you say rails, do you mean runners? I think so. Those are the big elbow macaroni looking tubes that come off the plenum in pairs of 2s, 8 in total obviously. ....there were a few different versions through the years, and yes, I think it IS possible to mix up the sides, and I think the gaskets for the runners and the base manifold also need to be correct to avoid a leak. ...I've messed with so many different TPIs with aftermarket runners, stock runners, aftermarketgaskets, etc. etc., and they're all a little different. I could be wrong...but....it can't hurt to double check and make sure they're right.

 

did you get 19# injectors? If they're too big or too small, without tuning, yes, that will cause fueling problems.

 

What brand fuel injectors did you use?

 

19lb bosh ll southbay

 

I'm gong to rip apart the car tomorrow and put no gaskets in and make sure there on there right and put it all back together and pray it runs right

 

Any luck?

 

Got busy with work definitly ripping the plenum apart tomorrow i have all new gaskets as well. The car did stall in reverse for the first time. It drives fine but in drive the idle is awful like it surges, park idle is rough but not nearly as bad i just hope i can get this thing running perfect its a shame such a beautiful car not running right.

 

I hear ya on that. A few years ago I purchased an 86 Fiero with the 2.8 that had sat for a while. Getting all the gremlins out of that so it would start, idle and run correctly left me swearing quite a bit for a few days.

 

I wouldnt have used those southbay injectors. If your taking off the plenum I would do all the gaskets down to the base. Reseal all the connections(threaded) to plenum and do the gaskets and orings on the tb. Get a new iac and iac gasket and check the tps voltage. Even though you didnt touch the screws,previous owner might have. If your going to get an iac get a name brand. Iac housing off and carb clean all the carbon.Timing light and do the timing. One more thing. When the plenum is off check the egr operation. Vacume on the line to egr will show you if its moving. Check condition of vacune lines. Cars this old have rubber hose issues and wiring could be chafed or broken. Also check all your grounds. Get the rust off and reseat.

 

Ok update the plenum gaskets were backwords so i swapped them and the car idles better but still not perfect. I had a code 23 which was the mat sensor i forgot to plug it back in under the plenum. I plugged that in. I got a code 43 (knock senosr?) when i started to accelerate hard and also a code 36. park idle is nearly perfect ,drive idle it still studders i do have a nasty exhaust leak im not sure if this is the issue its on the exaust manifold i believe before the cat ,i can hear it puffing when i drive, let me know what you think and thanks

 

Back off your timing a little bit. Try playing with the timing to see if that helps. You may have the distributor advanced too much if you're knock sensor is tripping. Vacuum line going to the vacuum canister in good shape? Sounds like you got everything pretty much right.

The exhaust leak, it depends on where at it's at. I had exhaust leaks from the manifold to Y-pipe and I just took a U bolt and put that near the rusted and broken studs from previous owner, and tightened the hell out of it. If that is where the leak is, to fix it right, you may have to pull the manifolds and put new studs in. However, I would just put in a set of 2.8 headers at that point.

https://www.summitracing.com/parts/p...model/firebird

 

I am new also. I hope it is okay to ask this question on this thread. I have a SBC 350 in the back of a 1977 Porsche 911. I just changed from an Edelbrock carb to a 1985 Corvette TPI. I think I have a bad lifter or two. Can I remove and replace these hydraulic lifters through the push rod opening once the rocker arms and push rods are out of the way?

I have a Comp XE268 flat tappet cam and L98 Corvette heads. Help. I don't want to take everything apart to get to the lifters, but maybe that is the only way???

 

You should post this in Tech/General Engine. at minimum you will have to remove intake and valve cover to replace a lifter.