weird cranking issue
#1
weird cranking issue
I decided to do a compression test on my '95 today before i spent anymore money on it. All the numbers were good at 115-130. But I noticed something strange. I have been having a hard start issue with it since day one. It will turn fast for a few seconds then stop and turn slowly, like it was trying to lock up. when it would stop it would do so violently. When i started the compression test though i pulled the fuel pump fuse so i wouldnt flood the cylinders out and it cranked fast and smooth nonstop. So that is leading me to believe that all of my current issues are with the fuel system. The only thing i can think of is that i have some really leaky injectors that are flooding the cylinders so bad in that first few seconds of cranking that it is hydrolocking it. Anyone else have some ideas? I think tomorrow morning i am going to pull the fuel rails and crank it and see what the injectors are doing. I have some spares laying around that i hope are good. I am hoping that this issue is also the same thing causing my extreme bogging when in gear and idling issues.
Could it be the fuel pressure regulator? i hope not since it is built into the tank module. Could it be the MAP sensor?
Could it be the fuel pressure regulator? i hope not since it is built into the tank module. Could it be the MAP sensor?
Last edited by QuadCabLuv; 11-21-2012 at 09:44 PM.
#2
Did you pull the fuel pump relay? Also check fuel pressure at the rail? Mine cranks slow when doing compression test....all spark plugs removed, throttle propped open, fuel pump relay removed and of course ignition coil disabled. If i just pull one plug and do compression test it will turn over fast.. but that's technically not correct way of testing.
Last edited by ReadRam; 11-21-2012 at 10:36 PM.
#3
yes I pulled the relay, no I havent checked fuel pressure. I will have to wait till fri night ehen I can bring home a fuel pressure gauge from work.
I did my compression test by pulling one plug at a time. Im notto concerned with it being the proper method or not. Im more concerned about my fuel issue.
I did my compression test by pulling one plug at a time. Im notto concerned with it being the proper method or not. Im more concerned about my fuel issue.
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So i hooked up a fuel pressure gauge this evening and found that my fuel pressure is actually low. It peaks at 39 psi and then drops to 35 and holds at 35. So it doesnt seem to be a fuel issue. But it is still hard to crank with the fuel pump running. I know 35 psi is a lil low but it should be enough to get it to run, and right now i cant get it to start.
So i decided to check for spark. At first i got some spark at the plug, but it was weak. Then it went away all together. So it appears maybe i had a weak spark issue that has turned into no spark. I am going to check for power at the coil tomorrow and for spark out of the coil. I am also going to pick up a better battery. If im not getting spark at the coil then im going to assume that either may cam position sensor or my crank sensor is bad. I will look at the FSM tonight to see if there is a way to test them.
I checked all my grounds and added some new ones, 1 rather large one. Ive got one from the back of each head to the body, one from altenator to bracket, two from the power steering pump bracket (one of wich goes back to battery), 1 large one from battery to body, and one from body to altenator bracket. That should be plenty. I even tried adding one to the coil bracket but still no spark.
Hopefully i can get some help tomorrow so i will have someone to crank while i check the coil for power and spark. I went ahead and cut the exhaust off just before the muffler to rule out a clogged exhaust, turns out it has no cat, or o2 sensors. Shouldnt the '95 have 1 o2 sensor? The gas in the tank is also turned south on me, looks like yellow ****, only a few gallons worth. So I will pick up 10 gallons of 93 to add in there and hopefully give me a decent enough fuel to burn, though it was running on whats in there now a couple of days ago.
So i decided to check for spark. At first i got some spark at the plug, but it was weak. Then it went away all together. So it appears maybe i had a weak spark issue that has turned into no spark. I am going to check for power at the coil tomorrow and for spark out of the coil. I am also going to pick up a better battery. If im not getting spark at the coil then im going to assume that either may cam position sensor or my crank sensor is bad. I will look at the FSM tonight to see if there is a way to test them.
I checked all my grounds and added some new ones, 1 rather large one. Ive got one from the back of each head to the body, one from altenator to bracket, two from the power steering pump bracket (one of wich goes back to battery), 1 large one from battery to body, and one from body to altenator bracket. That should be plenty. I even tried adding one to the coil bracket but still no spark.
Hopefully i can get some help tomorrow so i will have someone to crank while i check the coil for power and spark. I went ahead and cut the exhaust off just before the muffler to rule out a clogged exhaust, turns out it has no cat, or o2 sensors. Shouldnt the '95 have 1 o2 sensor? The gas in the tank is also turned south on me, looks like yellow ****, only a few gallons worth. So I will pick up 10 gallons of 93 to add in there and hopefully give me a decent enough fuel to burn, though it was running on whats in there now a couple of days ago.