90 mtx motor change problems

[bprotiva90]

just changed the motor in my 90 sho. can ran fine 4 days ago, then a wrist pin let loose. changed the motor and now the fuel pump primes and doesnt shut off, wont idle for shyt and when you give it throttle it bogs out. if you steadily raise the rpms it seems decent, but to just stab it if falls all over itself. im now at a loss of ideas. any suggestions would be greatly appreciated. im to the point of wanting to shred it:cuss::cuss:

 

[sperold]

Take a lot of the stuff off your old motor and install it on your new one, like the throttle position sensor & fuel pressure regulator. It would be nice to know if the new motor ran OK before the swap.

 

[bprotiva90]

the motor that i put in sat for about a year, and i changed over the entire intake plenum, all accessories, etc. im starting to wonder if the computer is somewhat fried?

 

[sperold]

Start from the simple and work towards the complicated. The computer will be last on that list.
Pull the spout and force the motor to run off the crank sensor (not the cam sensor) and see if it runs differently.
Make sure your plug wires are where they should be, and look for any sensors that are unplugged, including the 02 sensors on the exhaust.
See if it will give you any codes.

 

[bprotiva90]

ok, theres only one small problem with that. myself and two of my good friends have been over and over the engine bay countless times the last 48 hrs. i bought a small scanner from advanced (40 bucks) that just flashes and beeps the code and you decode that with the book it comes with. right now i tried using the scanner and it isnt responding to the car at all. when you turn the key forward for some reason the fan automatically turns on and runs along with the fuel pump issue. i know my firing order is correct and that everything is plugged in. the o2 sensors are new, therefore i dont think that would be the problem. ive changed motors in these before with my second sho and ive never had this amount of problems... thats why im hoping that you or someone on here can help my figure this out

 

[sperold]

I have heard of electrical plugs being criss-crossed, but that is a long shot, but check it anyways.
The sensors are really important.
Pull a plug and see if there is any oil on the outside of it (down in the plug well).
Is the coil pack from your original motor?
Try the spout thing.
Right now you are looking for something that changes your symptoms, not just things that make it better.

 

[oneqwicksho]

Pull the spout and force the motor to run off the crank sensor (not the cam sensor) and see if it runs differently.

How do you do this?

 

[bprotiva90]

yea, we switched the coil pack, plugs and wires. (plugs are a month old). the car wont start unless you shoot some starting fluid in it first.. shouldof mentioned that earlier.. i know that the little bit of hair that i do have left on my head will soon be gone due to scratching it.. lol the plugs are dry as far as oil goes

 

[shospeed143]

you may have a vacuum leak or a bad MAF sensor for the hard start. go out and buy some MAF cleaner and carb clean. use the MAF cleaner on the MAF sensor and then try and start the car after it has had some time to dry off. if the car still runs like shyt then take the carb cleaner and spray it around the intake gaskets and vacuum lines to see if the engine RPM changes. if it does then you found the vacuum leak.

as far as the fuel pump and fan running all of the time you may have a bad CCRM, computer, or a short in the wiring. if you are able to get some parts that you know work to test it out first then that is where I would start for that issue. but I would try and get the car running to make sure you dont have any codes that may come up before you go and start replacing parts.

 

[zach44102]

i had similar symptoms when i had my intake manifold off. try to loosen the manifold bolts, lift the intake up and readjust it. make sure all the vacuum lines are hooked up. and if that dosent work try running a bead of gasket maker on your old intake manifold gaskets.

 

[oneqwicksho]

you may have a vacuum leak or a bad MAF sensor for the hard start. go out and buy some MAF cleaner and carb clean. use the MAF cleaner on the MAF sensor and then try and start the car after it has had some time to dry off. if the car still runs like shyt then take the carb cleaner and spray it around the intake gaskets and vacuum lines to see if the engine RPM changes. if it does then you found the vacuum leak.

as far as the fuel pump and fan running all of the time you may have a bad CCRM, computer, or a short in the wiring. if you are able to get some parts that you know work to test it out first then that is where I would start for that issue. but I would try and get the car running to make sure you don't have any codes that may come up before you go and start replacing parts.

We swaped the CCRM didn't help same problem, swaped maf and same problem, ( all off my running sho) did the carb cleaner method yesterday and no change there. So no leaks, swaped TPS did. Nothing, it needs an IAC I swaped mine in it an it idled a little better but still ran like shit no power cuts out and lean, really lean, backfires through intake. Secondaries are wide open ( something electrical tried everything else) so I'm lost

 

[trainguy1989]

just changed the motor in my 90 sho. can ran fine 4 days ago, then a wrist pin let loose. changed the motor and now the fuel pump primes and doesnt shut off, wont idle for shyt and when you give it throttle it bogs out. if you steadily raise the rpms it seems decent, but to just stab it if falls all over itself. im now at a loss of ideas. any suggestions would be greatly appreciated. im to the point of wanting to shred it:cuss::cuss:

Did you ever disconnect the PCM(computer) from the main wiring harness? You just described what my car is doing perfectly too. I cannot pull codes either.
http://www.shoforum.com/showthread.php?t=107495

 

[oneqwicksho]

problem solved

Well everyone the car is fixed the computer was fried/bad swaped it out with a spare and fired right up

 

[bprotiva90]

yes, damn computer. if that wouldnt have been the problem then i was gonna call it a total loss. but who couldof guessed? i thank you guys for your input. the car is now going to a new home. ... hey mike, wanna change another motor? lmao

 

[oneqwicksho]

... hey mike, wanna change another motor? lmao

Sure! Line it up ,but this time I'm charging ya lol