No Start after car has been running and shut off

[cp___32]

Hey,
I've got a 91 Civic CX, 5spd, 1.5L engine with the DPFI system....maybe around 200 000KM on the motor...not too sure since it's not the original

I've done some searching on the forum but can't seem to find a definitive answer to my issue (Which has unfortunately gotten worse).

My problem has generally been that if I were to have the car running for even a short period of time, bring the car to a stop and shut it off (for example if I were to go and get gas) when I try to start the car again it will not. The motor cranks but doesn't fire. Usually if I leave the car to sit for 2 - 5 minutes and then try again the car fires right up and I continue on my journey.
Now the car is doing the same thing only I haven't had the pleasure of driving it first...it's HOT today so I don't know if that's partly to blame but I went to start it this morning and it will not start.

The ECU gives me a code 16 which is the injector code as far as I understand.

I read a few places that the cause might be from using anything but the exact OE replacement plugs and wires. I'm not quite sure if that's the case, but I do have OE wires, I think the plugs are NGK's but I might be wrong.

Brief list of new parts and known good parts are as follows:
New Alternator
New Distributor, cap and rotor
New Battery
Plugs and wires were changed last year
Starter is good and I don't believe this is a starter issue since it's done this while the car was rolling and I shut it off and it would not restart with the engine turning plenty fast.
Air Intake system with high flow filter
Fuel filter replaced a couple of years ago


Thanks for the help

[amy@af]

there are 3 general things it could be.

1) main relay. when you turn your key on do you hear a small click when the check engine light turns off?

2) ignitor/coil in the dizzy. for that you need to check for spark. no spark then it's one of those.

3) IAT. for some reason i'm leaning towards the other 2 but I have seen it happen.

[cp___32]

I'll check on the main relay click. I honestly haven't paid too much attention to all the clicks and beeps lately, but it appears that the car does everything it's supposed to except detonate the fuel in the cylinder. So it cranks fine, just no vrooooom.

I'm not one for assumptions because I've learned the hard way that assuming a part is good isn't a wise idea it's always best to double check it, but the Dizzy is NEW. Like from a parts supplier professionaly rebuilt, shiny, wrapped in plastic new, not just picked up from a scrapyard. So at this point I'd go out on a limb and say that's probably unlikely (but obviously not impossible)

What's an IAT? Would the main relay throw a code 16? Unfortunately my tools are across town where I've been rebuilding my motorcycle so I can't do extensive testing here, and I was thinking if I went to the scrapyard I'd pick up a few different things to make the trip worthwhile. With the DPFI could it still be the injector resistor if there even is one? Is there a separate Fuel Pump Relay or is that controlled by the main relay?

I do have a spare motor...is it worth swapping over the whole injector assembly?
I think there's a small leak near the top of the tank, would that have such an effect as to prevent the system from building pressure?

[amy@af]

no joke i have seen (more than once) brand new dizzy out of the parts house, pinned wrong. crazy but when you have a swap shop, you tend to see crazy things.

it's most likely the IAT. Intake Air Temp. is what it stands for.

i don't recall seeing a main relay throwing a code 16. the click is small and quiet. it happens right as the check engine light blinks out after you turn your key on before you get to crank position.

you can test the IAT with an ohm meter.

i am really leaning to an ignitor in the dizzy or the IAT

[cp___32]

Hmm...I'm having trouble sourcing an IAT locally (London, Ontario, Canada) the closest thing they list anywhere is a Coolant Temp Sensor which isn't what I'm looking for right?

I do have a spare DPFI motor but I don't know if the sensor on that is any good since I only drove the car a few km to the shop I pulled the motor at. I also happened to have a bunch of MPFI components including the throttle body and the big fuel rail and whatnot. Anyone know, should my IAT be junk, if the one from the MPFI would work or does it have to be the one from the DPFI since that's what I have in my car currently?

[cp___32]

Hey,
Just to clean up this issue...
I replaced the main relay (located under the dash behind the hood pop lever) and that seems to have cured the issue.