sorry, another "i can't get my rebuild to start" thread
 

yes, i have searched.

i have tried everything I can find in other threads and am having no luck.

i have an 89 gtu, stock replacement motor from mazda. everything is together and the engine will crank, but only fires for a second (at best), then dies as soon as i let the key go back to run. it never makes it past a couple hundred rpm's. it does pump out some nasty smelling blue smoke while cranking, which is just lube from the rebuild burning off, right?

i pulled it around the block a few times with my brothers truck, but it will not run on it's own. it would rev when i popped the clutch, but that's it. if i gave it any gas, it backfired, loud.

it shouldnt be flooded, as I have un-flooded it about 18 times. pulled the plugs and egi fuse, cranked, and so on.

the plugs smell like gas and i have a new fuel pump, so i know i'm getting fuel. the trailing plugs seem to have a little gas on them, but the leading are clean. i have tested spark and it is working (felt the shock in my arm, just in case).

i have gone back and forth with timing adjustments, but nothing helps. there are a few spots where it won't fire at all, but i tried everything i can.

my only other thought is to double check and make sure i wired the injectors right. and I have one piece of what looks like vaccuum hose, but bigger that I apparently didn't find a spot for. it looks like one of the connector pieces in the solenoid valves, but bigger and it has an orange (i think) spot on it. i doubt it would make it not start, but if there's a huge vaccuum leak, i guess that might hurt it.

i'd love to hear any other suggestions, as I've done everything I've found in other rebuild threads.

the only other thing I can think is that my oil pressure gauge stays at the top, so I must have that sensor hooked up wrong.

oh, and i'm sure i have my plug wires in the right order too.

thanks in advance.

brian.

try restabbing the cas, turn the engine to line up the yellow mark on the pulley to the line and align the cas and try again, if the teeth were off, u can run out of adjustment range before you get timing to where the motor likes it

thanks for the response. i tried that a couple of times, but just went back and did it again. i pulled out the haynes manual and it turns out i was doing it wrong, :pat:

so, i did it according to the instructions. turned the key and it fired, revved up to 2k rpms, then died. it did that a few times.

i tried it again, this time i tapped the throttle. it revved to 3k, backfired, then died.

i can't really try anymore tonight, making all that noise :) but am i on the right track? what else should I try tomorrow?

thanks again.

i tried again today and got about the same thing. it started, revved to 3-4k and died. it did that a couple of times, then started sounding rough and not going anywhere again.

i'm thinking i'll try to tow it again and see what happens, but if anyone has any other thoughts I should try, please let me know!

If its starting, then towing it won't help anything.... why roll start, when the starter starts it? ;)
Check all your vac lines, block off plates, anywhere that there could be a leak big enough to cause it to stall out.

I know I had a similar problem when one of my blockoff plates didn't seal correctly. It would fire up no problem, rev up then just die off right away.

make sure the afm is plugged in

thanks rotard, i'll check all of the vac lines in the next few days.

NOPR, the afm is definitely plugged in.

pressure test the intake manifold FIRST.

After you've fixed any and all vacuum leaks, then move on.

Check the timing with a timing light and make sure it's set accuratly.

Backfiring.. hmm.. Check the connection to the AFM, plug wires are in the correct places.

i went back at it again tonight. the AFM looks good to me. i found one small vacuum leak and fixed it, but got the same result as before.

after unflooding (the plugs were wet) i cranked it and it fired up, went to 3k and died. so i sat in it, did it again and once the rpms climbed i gave it a little throttle. It held between 4-5k, but died if i let it fall below that.

plus, if I adjusted the throttle at all, it backfired.

I tried a few times, each ran harder and harder and with more and more backfires.. there's lots of blue smoke which i understand is normal, but i stopped for the night cuz the neighbors came out to see what the noise was...

any thoughts?

ok guys, i know it's been a while here, i didn't do much with it over the winter, but i'm back to square one here.

i just finished taking apart the manifold and vdi and checking for leaks. i found a few candidates (bad gasket on the bacv, a couple of vacuum hoses not connected, etc) but am having the same results.

i put everything back together, turned the key and it fired, but died immediately. now it's not even getting up to 3k like it was before. if i touch the gas pedal it backfires and the neighbors look at me funny :)

anyway, I'm out of ideas. above someone mentioned pressure testing the manifold. how do I do that?

i did notice that when I have the key on run i can hear the injectors clicking, like they're firing. is that right?

any other suggestions?

Read all above. I had the same problem and I conducted the AFM test which is in the FSM and it was slightly off on the 3-5 plug test. Got a new one through becks on ebay and fired right up been running great for a two weeks. Highly recommend conducting the test's in the FSM after 20 years of sitting on the care anything you move could fail even if you did not mess with it.

My friend had a similar problem and it turned out his afm was hooked up wrong.

I can almost assure you it has SOMETHING to do with the AFM. I've ran into similar problems with several Mazdas (not just RX's) where the plug is not connected or some how the wires have split.
Each time it will start up run for a bit then die.
CHECK YOU AFM

ok, i followed the fsm and the resistances seem a little high if I'm reading the meter right.

i'm going to try a digital meter just in case i'm reading it wrong, but is that what would tell me it's bad?

just got another AFM from a member here and still nothing. it is a little different though. it does a few real low pops then dies.

i'm going to check spark and i'm charging the battery and see what's going on there.

sounds like a vac line is off
I am having the same problem right now.. I took off the UIM and found a vac line off from the LIM on the inner side , so I'm trying to find out where it goes , then I'll tell you the results.. but I'm guessing its similar

double check that you have the fuel injector plugs are in the right location, i flubbed that up once

thanks guys.

i have had the uim apart soo many times and it seems like every time i take it apart again i find something else disconnected. but last time i took it off, everything looked right.

actually, i found that my fuel lines were backwards, and then once i fixed it, fuel was not making it through the return line. i got a new secondary rail and have yet to try it out.

i'll triple check the injector plugs too, thanks.