Diagnosing the Racecar

[turbohcar]

I have been having trouble with this beast for almost a year now and no result has come of it. My friend and I have built a Hornet/Wild Thing racecar for the dirt circle. It's a 91 N/A (turbos and AWD aren't allowed) 5spd 2.0 4G63. Now, we bought it from some hillbillys in Ohio that had a Mitsubishi graveyard. The car came in stock condition minus an ECU. We thought, throw a good ECU in and we're good to go.....Wrong! After two ECUs, eight spark plugs, four plug wires, two coil packs, two transistors, two CASensors, two MAFs, four injectors, a fuel filter, a battery, a fuel pressure regulator, and misc. other things this thing still doesn't run correctly.

Finally, it's warm enough to do some work and a friend graciously let me borrow his logger to finally get this thing figured out. Here's the log I came up with. All of these are done with the gas to the floor at the cut out limit. It cuts out around 5k RPM and acts like fuel cut. Sometimes it does this when climbing in RPM too but really only cuts out at 5k (on the stock tach).


RPM 4343
INJP 11.77ms
KNCK 0 (I don't think the N/As have a knock sensor)
TPS 99.6%
INJD 42.1%
TIMA 21*
COOL 85.6*C
AIRT 28.6*C
EGRT -28.2*C
BATT 13.0V
ISC 23.4%
MAFS 855.4Hz
ACLE 0%
02 0.66V

Here's another

RPM 3312
INJP 11.26ms
KNCK 0
TPS 99.6%
INJD 30.4
TIMA 22*
COOL 87.5*C
AIRT 30.0*C
EGRT -28.2*C
BATT 13.2V
ISC 23.4%
MAFS 610.1Hz
ACLE 0%
02 0.78V

Please help. If you've got any ideas let me know. I did notice that injector duty is incredibly low and don't know how to explain it. Thanks for any help tuners.

 

[turbohcar]

I finally got it home from its former residence in the storage unit. For whatever reason, now it doesn't even want to start. I've got spark, but it appears weak (not as strong as it should be) and the plugs come out black. These are brand new plugs and they come out pitch black. Oil consumption is most likely the cause but, I can't see how it could affect it this seriously. I've tried putting a spare ECU and CAS (the CAS and ECU were junk, no reading on the datalogger) I had on it but get no result.

The spark plugs are now sparking inside themselves. As in, they are not sparking at the point, it's down inside between where the plug threads into the head and the base of the projected point. I even took the plugs out of my turbo car that were in good, new condition and it even ruined those ones.

There is also an incredibly loud audible sound coming from the top end of the motor. The top end doesn't sound quite like the precise, calm sewing machine it's supposed to. More like a sewing machine over-juiced on steroids going too fast and hammering itself into oblivion. I'm not sure if this has anything with the valve timing possibly being off but it's a thought. I'll check valve timing tonight and see.

 

[1.8laser90]

i hate to say this but your timming jumped and bent some valves! my timming jumped on mine, that noise you are hearing is the valves hitting the pistons. You could try putting it back in time but figure out what caused it to jump or if the belt is broke if its not starting anymore... more than likely you have some bent valves

 

[turbohcar]

The timing belt isn't broken, I've already checked for that. I am going to check the timing marks on the cam gears tonight to make sure that the valves are in time. That does kind of scare me though that it might need a motor transplant. If anything, I may end up just getting a used motor to throw in it along with a good wiring harness. The one that is in it has been hacked a little bit and I'm afraid that may be some of the cause. I'll check tonight.

 

[turbohcar]

Checked valve timing last night only to find out that it was right on the money. Any other ideas?

 

[1.8laser90]

everything was lined up correctly ? cams, crank, oil pump and balancer shaft???... becuase that noice in the cylinder head leads me right to that

 

[1.8laser90]

hmm this is kinda wierd my 2.0 just jumped timming for the 2nd time today... about 30 miles on the new cylinder head from the last time! so this car is goin ! i love my 1.8l!! your lucky !

 

[turbohcar]

I tried grounding the head last night to make sure it was getting a proper ground...nothing. I looked back at the pictures I took of the cam gears aligned and the dowel pins are pointing down. I have been told that they are supposed to be pointing up. What's the deal? Thanks

Brett

 

[turbohcar]

Well, I've ran into a really strange situation. I went ahead and lined up the cam gear timing imprints again. This time, I found that the set of cam gears that are on this car, have two sets of imprints. One on each side 180* from each other on each cam gear. I made sure that the dowel pins were straight up and lined up the marks accordingly. I'm still trying to find a vfaq on how to make sure the piston is at TDC as I have forgotten this valuable information. I did do a quick chec with a screw driver and #1 is definitely farther up than #2.

Oh, and, I plugged a spare, brand new plug into the wires and grounded it to the valve cover just for fun. Spark in the new plug is very evident and defined, like it should be. I did notice that it was jumping around quite a bit though. I'm not sure if it's a good or bad thing but, it was sparking at the electrode correctly but was jumping around on the pickup quite a bit.

I'm sure it's probably nothing but I figured I'd add that in to cover all aspects.