I just bought a chevy 85 pickup that a friend of mine many many years ago wired an 89 Camaro TBI 305 into. Well I sold the truck to a buddy then he sold to a buddy who the truck stopped working on. He was an idiot and didn't know wtf was going on so he decided he wanted a 4 barrel on it pulled the tbi and intake off and sat a 4 barrel on it and never done anything with it.

I got the truck back TBI missing he blamed the not starting on the TBI when it actually ended up being the fuel pump if that tells you how retarded this guy is. Anyway I had some TBI units just laying around my shop so I started with the first one I grabbed it had a bad injector it wouldn't even pulse or turn on period even after tapping on the TBI a couple times to maybe free it up. So then I pulled the injector pod off the top of the TBI and I put the pod off another TBI I had. Well it had a half stopped up injector it would spray half *** then it would drip every once in a while. I figured hell time for some SeaFoam.

I said well I better make sure this TBI and injectors is even correct for my engine before I go spending $9 on SeaFoam. So I wiped the top of the injectors off the best I could with all the rust I could hardly even read the numbers but was able too after some dw40 and ten minutes of rubbing. Come to find out the injectors was 2.8L v6 injectors and the smallest injectors you could even have some I was disappointed right off.

So I called around some buddies and a friend had a TBI in pieces with some injectors I looked them up and they are 5.7 61lb/hr injectors. So I said screw it those should work. I mean hell I have put a 600cfm carb on a 305 stock before and it handed all the fuel that carb could give without any issues so I figured one step on injectors sure no problem. So I put the injectors in and it's flooding out like crazy. Both of the injectors look as if they are spraying right.

I thought well maybe the MAP sensor is actually working now that the injectors are both pulsing. So I changed the MAP with another one I had laying around. Didn't change anything at all. So now I'm thinking maybe a vacuum leak on one of the gaskets I did see the gasket of the pod act as if it was about to rip so maybe it's sucking in some air which is causing it not to even start and flood out so much. I'm definitely not an expert at TBI. Maybe the injectors are just too much for my engine.

I have full length headers with 2.5" collectors and 2.5" pipe with flowmasters and turn downs before the rear end. I also have a 12x3 open K&N air filter but that's all the bolt on mods I have done. I would think with those mods it would be able to take some extra fuel but I could be wrong.

My question, is my injectors the problem with the flooding are they just so much better then 305 injectors that it just can't burn the fuel? It has crap Bosch Platinum plugs in it I thought they could be the problem. I never liked those plugs I'd much rather run regular AC Delco or even NGK plugs. Maybe the plugs are just not burning hot enough to burn the extra fuel.

 

They are not better, the flow rate is different, too much fuel causes a bog before it strarts accelerating.

 

I had 2 vehicles that had GM type holly tbi, the one that had a 2.8L had a bad injector so I took the pod off the 5.7L tbi & put it on the v6. It ran pretty good not to overly rich. I ran till I got a replacement. I think you should look into how much vacuum the engine is making, check the timing, ect sensor resistance.

 

I'll definitely give that a shot. I really can't see how a step up on injectors could flood the engine out so bad that it can't even start. I would imagine when running it would run a little rich having the bigger injectors, but not running at all seems strange to me. Thanks for your input.

 

I didn't mean it as being better in general just more fuel. I should have worded that differently. With everything I said before that sentence it should have been obvious what I meant.

 

id change the plugs regardless. Stock for 305 tbi is R45TS if I am not mistaken. The extra fuel could deffinately cause this. The computer tells the injectors to fire for x amount of time but at this pound rate that x amount of time could be way too long.

 

That makes a lot of sense. I changed the plugs to regular AC Delco plugs I really wanted to do Accel plugs but I just couldn't afford the extra money for them. After installing them the engine started right up seemed like it was running a little rich and also running pretty rough. After tickering with it for about 5 minutes truck ran out of gas and wouldn't start at all. So I'll have to do some more when I can afford to put gas in it again.

Thanks for the help guys I'll keep you posted on it.