The Central Hub for DSM Community and Information

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. This is where the DSM platform history is documented and archived. Log in to help us in our mission, and to remove most ads from the browsing experience.

91 laser wont run

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

seether221

Probationary Member
27
0
Sep 7, 2012
Fort Oglethorpe, Georgia
Okay so i got a 91 laser that had a snapped belt, got it for a steal so i couldn't refuse. Bought a new head got it resurfaced, ordered completely new gasket set, rod bearings main bearings and piston rings, bought new head studs also. Put it all back together didnt run, tore it back apart to find number one piston hit the head 0.o I'm not sure what happened so i got another head had the machine shop completely go through it, ordered another new timing belt got arp head studs head gasket set and new pistons. Put it back together still have fuel spark and timing is dead on, I'm completely lost when trying to start it backfires through intake
 
Definitely gonna check mechanical timing again today. I've checked cas it's not one 180 out and according to my Haynes manual my firing order is right, thanks for all the replies
 
I just checked mechanical timing its still right, pulled plugs out and they were soaked in gas and there was some fuel sitting on top of piston. When i first got the car there was a Pinout sheet for wiring up an safc but not one in the car, thats were i will look now
 
New ecu, still wont run. Com on guys im so lost. Timing is good firing order is right. What could it be
 
You've got fuel, spark. Compression should be fine with a new head. New ECU rules out that problem. Only thing I can think of is electrical timing. Sounds like it is firing too soon while the intake valves are open. Try adjusting the cam angle sensor to retard timing. Your boost gauge is going to zero when you turn the key on isn't it.

Also check the coolant temp sensor wires. If they are broken or unplugged the engine thinks it's 140 below and adds a ton of fuel.

Good luck
 
With new ecu backfires through exhaust and intake, boost guage goes to zero when starting temp sensor wires are plugged up. Would a temp sensor let it fire and get fuel but not start? I've adjusTed cam angle sensor to every position possible with no luck.
 
Coolant temp sensor will make it hard to start and run crappy. Sorry I can't be more specific. Just trying to check out the most likely problems.

What I don't understand is the backfire thru the exhaust and intake. From what you've said everything should be perfect.
 
Thats what i dont understand, i have shocked and rechecked everything. Although one thing i have noticed is the first time i try to fire it up before i start working on it, it smells strongly like fuel.
 
From the smell of fuel I'm leaning towards ignition timing being way off or injectors are stuck, could either of these be a possibility
 
Did you bleed your lifters down? Valves might be hanging open, did you do a compression test?
 
Tried compression test but no luck finding a tester, compression numbers are unknown, coolant temp has been replaced just early, got a backfire that sound like a shot gun when first turning the key but thats all.
 
Tried compression test but no luck finding a tester, compression numbers are unknown, coolant temp has been replaced just early, got a backfire that sound like a shot gun when first turning the key but thats all.
Everyone has asked and i will ask again. Did you bleed the lifters before installing them? If not, that caused the valve to hit the piston on the first head.And it may have bent valves on this head too. With the backfire through the intake, either valves are bent or they just arent closed completely.
 
Add Value - Be Respectful - No Trolling - No Misinformation - Participate Often!
Support Vendors who Support the DSM Community

Build Thread Updates

Latest Classifieds

  • For sale 4G63 Forge Motorsports BOV
    Original Forge Motorsports bov. Adjustable with over 80 clicks on the dial. Nice to use for...
    • Galant665
    • Updated:
  • Wanted 1g 1991 Black Cherry Eagle Talon
    5-speed
    • bamatalon
    • Updated:
    • Expires
  • For sale Misc Left Over Parts
    Hello, I have a few left over parts for sale, these do not include shipping, please pm me for a...
    • r3dmak
    • Updated:
    • Expires
  • For sale Alpha Injection Clinic 2200cc for 4G63 DSM/EVO
    I have a set of Alpha Injection Clinic 2200cc high z injectors for DSM/EVO. I am stepping up to...
    • spoolinpos
    • Updated:
    • Expires
  • Wanted WTB 2g half rad
    ISO of a 2g koyo half rad or something equivalent.
    • Michael Wucher
    • Updated:
    • Expires
Back
Top