I just changed my stock injectors on my 88' n/a to 660cc. I used four of the 660cc injectors for the primaries and the secondaries. Now the car will not idle and it dies every time I drive it and push in the clutch and let off the gas. Does anyone have any ideas how to solve this? Also what are the stock injectors on an 88' n/a? Thanks for all the help and advice. Have a Good Week, Jimmy

 

Of course it won't idle! That's way too much fuel.

The stock injectors are 460CC.

Why did you swap the injectors?

 

How are you controlling the 660's? The 86-91 non turbo already runs pig rich and unless you have some sort of controller to dial them back considerably, you will have made the situation even worse.

What sort of mods have you done to need to put 660's in? The stock 460's are good for about 220-225HP, which is more than a non turbo engine is going to put out.

Normally upgrading the injectors on a non turbo is just about the very last possible thing you want to do.

 

I have a K&N cone intake, racing beat downpipe, HKS exhaust, walbro fuel pump. I plan on having the engine street ported. What are the biggest injectors I could get away with? Would a 460cc primary and 550cc secondary set up work? Thanks for the feedback so far.

 

With your mods you have radically too much fuel, even with a street port you have radically too much fuel.

At very least, you need to put the stock 460's back in (and probably will still run rich due to the Walbro) or get some sort of fuel controller such as a AFC or RTek.

Again the non turbo runs rich... to make more power you need to either increase air to balance that out, or decrease fuel. This is not some silly Honda or mitsu 4 banger that the first thing you do it bolt in bigger injectors because they flow a lot of air, but not fuel.

 

if you are wondering why it matters jimmy...


injectors run on a voltage scale, so the more voltage they see the more they inject, If you've put in injectors bigger than stock without modification, the ECU has no idea they are there so sends the voltage that the 460's would need. both the 460's and 660's run on the same voltage scale, the signal the ecu is sending out will open the 660's the same percentage as it did the 460's, except now you are using an injector that is 30% bigger and putting in 30% more fuel with the same signal from the ECU.

End result is a pig rich situation which will flood out an already rich running car out at idle.

You can buy engine managements as stated above, apexi SAFC is cheap as hell but also **** because of the way it adds/subtracts fuel. you should definitely look into something to take full advantage of your mods list and that street port youre planning

Go visit the reading threads, then come to the 2nd gen forum. welcome aboard.

 

Injectors are actually PWM'd and are duty cycle based, not voltage based. The amount of fuel injected is based upon injector open time, not the voltage they see. But aside from that, the post above is totally correct. The ECU has no way of knowing what size injectors you have installed so if you put in larger ones, it continues to run merrily along assuming that much small injectors are present.

And ditch that fuel pump. That pump supports 400HP and will considerably increase fuel pressure.