cranking, no start

Jetfoi34 · Post by **Jetfoi34** » Fri Mar 21, 2008 2:56 pm

so i thought i had everything good to go and ready
this is my first swap by myself

engine is cranking, but it will not start
ive checked and im getting spark at the ends of the plug wires, there is fuel pressure in the rails

what are some reasons that this thing wont fire up?

JeffD · Post by **JeffD** » Fri Mar 21, 2008 4:49 pm

first of all, what did you swap in?
any case I would double check all of the connections that go to the Fuel injectors, also, if you have a extra fuel injector try plugging it into one of the end harnesses that you can get at and see if it works.
make sure that your spark plug wires are going to the right cylinders too, I've messed that up and my car wouldn't start.

Jetfoi34 · Post by **Jetfoi34** » Fri Mar 21, 2008 5:30 pm

91' 3.1mpfi 5-speed to a 3400

spark, im getting spark on every cylinder, double checked spark plug routing

fuel, im getting pressure in the fuel rails for sure
is there a way to check the injectors without taking off the UIM?
how can i go about making sure all injectors are firing and are in working order

JeffD · Post by **JeffD** » Sat Mar 22, 2008 3:53 pm

just to make sure that everything else is working right, take some ether and spray it in the intake and see if it'll fire, then go from there.
there is a way to check the injectors, but you need the a breakout box to actually test the switching of the injectors. What injectors are you using? Rochester ones or bosch? I'm not sure, but the injector drivers in the computer may not work with injectors with a different resistance than the original Rochester ones.
the engine is still MPFI right? you are going to have to take off the UIM anyway to check them. If its SFI, using the OBDII computer, you can check the injector resistance from the injector harness.
Really, the upper intake isn't too bad to take off, takes about 10 minutes for me.
Have you checked the engine for cranking compression? if no, I'd do that first, then go on to the fuel system.

Duke 3D · Post by **Duke 3D** » Sun Mar 23, 2008 3:34 pm

my best opoion would change the spark plug wires. but you said your getting spark. try checking the fuel input you might be flooding it. also try checking the fuel lines. post back when you get a chance

JeffD · Post by **JeffD** » Mon Mar 24, 2008 10:02 am

You might Want to talk to someone with a Noid light set, those are specially made for testing solenoids and fuel injectors.
I'm not sure what year they started doing it, but if you press the Gas pedal all the way down and crank the engine it will disable the injectors to clear up a flooding issue.

Post by **Cliff8928** » Mon Mar 24, 2008 1:00 pm

Autozone has loaner NOID light sets...

cramez · Post by **cramez** » Tue Mar 25, 2008 12:27 am

Yeah, definitely try to get some NOID lights on the car and crank it over, that'll at least tell you if the computer is firing the injectors. I don't think it should matter, but just out of curiosity, which injectors are you running, the 3400 ones or the old 3.1 ones?

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