MFI.MPI relay keeps blowing/temporally

[o00slim00o]

I purchased a 91 Talon N/A in non running condition, narrowed it down to the ECU being junk and replaced it. i fired it up only to find the head gasket was blown. I replaced that and once it was all back together i fired it up ... it hesitated a lil but ran for about 15 min then i drove it a block down the street and back and shut it off ... an hour later i tried again and it wouldnt fire, i let the car sit for 2 days and went out this morning and it started right up on the first try again it ran about 15min and shut off i checked for fuel and it was getting it to the fuel rail but the injectors arn't firing so i replaced the MPI/MFI relay and it fired right up again for about 10min this time then wouldnt fire, replaced the MPI/MFI relay again and loan behold it fired again for about a min and shut off, now i got 4 MPI/MFI relays that are junk and the injectors wont fire,

what would cause the relay to keep blowing

 

[clipto]

Try looking into a short circuit or the wiring to the injectors, or in an injector itself.

 

[ecliperacen88]

yup sounds like a wiring issue, check and make sure nothings grounding out and that there are no slits in the wires

 

[o00slim00o]

when i got the car the whole wiring harnest was untaped already, all the wiring from the firewall front looked good ill check the wiring inside the car from the MPI/MFI relay and the ecu tonight thank you

**UPDATE** so i went out to look at it again tonight and left the same MPI/MFI relay in it that was in it last attempt yesterday and it fired again it ran about 10 min and shut off then no fuel.. so i swapped with one of the relays that "blew" yesterday and it fired again for a min or two and then shut off again ??

Apparently its not "blowing" the relay just something stops working for a while
because after it sits for a day it fires up again

any suggestions/ or any one wanna buy this car if they think they can fix it ... im about to take it to the yard or trade it for a VW corrado and its a nearly mint 1st gen

 

[Steve91]

Try looking at the injector resistor box it's located on the firewall should be right next to the battery, a little silver box.

 

[1GspoolinDSM]

I normally just sit back and let other members answer. But I just went threw something similar on my 1g this weekend, although Iam turbo but it might help you or others.
My car would also shut off after about 10 min or so of driving/idling. Let it sit for a while and it would fire back up and act like everything was good then shutdown again whenever it warmed up. I swapped in other relays and it would idle for a min but shut down again. Compression good, timing good,rail had fuel pressure, but there was no spark. Turned out that my cam/crank angle sensor on the side of the head was on its way out the door, whenever heat from the motor soaked the sensor the electrode would stop firing the 5v signal to the ecu. A buddy had a CAS in his parts pile I swapped it in and NO more shutdowns =-) Good luck I hope you get it figured out!

 

[dral24]

what he said, that was my guess could be the cas check it out