90 SC starting problem

kevenj90sc

Registered User
ok i've had an intermittent problem for a while, my car would occasionally crank over for a long time before starting but most of the time it was fine, but now will hardly start at all. this morning she started fine but while idling it just died (NEVER did that before). It started back up but took a while, then when i tried to rev it up a little, it sputtered and shook...so i pulled it back in the garage and drove the bronco to work. Just got home from work and tried to start it, cranked over but no start.....i tried it like 3 times, then on the 4th try she started, idled fine for a few seconds, then sputtered but didnt die, then smoothed out a little, but all this time the tach is not working. tried to rev it up a little and it just sputtered, tach needle bounced a little.......So what's going on here? Cam Sensor?, Coil? , crank sensor? I should mention i replaced the DIS module about a month ago when it was acting up only sometimes, and the old one tested bad. i guess the new DIS could be bad but is there something that could 'pop' a new module in a short time? i cleaned the mounting surface and used the heat sink grease....... Also i'm getting no 'check engine ' light, but have not checked for codes with a scan tool yet (i can get my friend who owns a shop to do this Tuesday).....any ideas???
 
I had/have the same problem...

I had the EXACT same problem with my 90 SC, I first figured it was my Battery going bad because of the hard starting so I replaced that, and it seemed to help a little bit. Then The next day I was heading home from class and while sitting at a red light my engine's RPM's started revving up and down quickly within a 300 rpm range through all range of throttle (EXE. if i held the throttle at 3,000RPM it would fluctuate between 2,850 and 3,250 rapidly) which caused me to drive with my clutch partially depressed to ease this rapid fluctuating from hurting my drivetrain. This problem then went away like 30 seconds later. Then my whole car lost power and soon sputterd and died. I later tested my Alternator and found it was dead, so 190.00 later I figured I was set.....WRONG! I got into my car and gave it a crank after fully charging my battery and got a hard cranking and then a quick cranking which sounded like my engine had no compression or spark (similar to when I first noticed a problem) So, I finally got it started after some cranking it wanted to die when idling like my injectors were clogged or something, then after a few revs it would clear right up and idle fine. I also noticed all my gauges wern't working at all, and my "Check Gauge" light was on after long searching though my wiring and ignition diagrams in my Ford tech manuals I figured to go the next cheapest route and replace my Cam sensor (Thank God I work at Autozone and get a discount on this stuff!) this seemed to bring the gauges back to life and fix the wierd throttle flux, but I still have the hard start problem every once and a while, and my car seems to have never idled the same as before it runs a little low when idling and bucks a little.
But I too am searching for the cure to this problem, If anyone out there can help us fix our similar problems please let us know. I hope this helps you narrow down your search kevenj90sc let me know if you figure anything out or need me to look something up in my Ford Shop manuals, I'll be glad to help.
See ya,
Greg Roll
 
Cam sensor most likely

But the DIS or cable/connectors between the 2 are also possibilities. Loss of tach is Cam sensor 9 times out of 10. ;)

Lee
 
For Keven,

My first check would be to dig around and pull the vacuum line off the fuel pressure regulator looking for signs of fuel. What you describe sounds like weak, or lack of spark. But if your plugs are old, and the problem has been building, Fuel fouled spark plugs could be what's causing your poor idle and hard start.

How's the fuel economy been since the problem started happening?

The other thing to check that is pretty easy is to check for spark during a no-start condition using a timing light on one of the plug wires. If you are getting no spark, well then that's an entirely different problem.

That's always the first task regardless of how complex the engine. Fuel or Spark.
 
well i was thinking my occasional hard start could be fuel pressure so i put a gauge on it and it's at 34 psi at idle and once the car was running i never had a performance or drivability problem, but i was gonna change the fuel pump because it's very noisy and the car has 117,000 miles on it. The plugs and wires have only 5000 miles and i used Motorcraft double platinums and motorcraft wires (i figured since the originals went 112,000 they must be ok). But i know my problem is spark related now cuz of the tach not working when i did get it to start on the 4th try. i think everything points to the cam sensor so i'll get one at work tomorrow ( not autozone, NAPA... ha ha ). we have a tester that will test the DIS module and give a printout of all the circuits so i'll check it too, but like i said it's a month or so old and the old one did test bad. Is there anyway a bad cam sensor or something else can damage the DIS module? anyone know?
 
Back
Top