Mitsubishi 3000GT & Dodge Stealth Forum banner

1 - 19 of 19 Posts
4

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I have a 1995 VR-4 Spyder that I'm experincing bad hesitation (believe to be misfiring) It was slightly present when the car was stock. Now that I have added Stillen Intake, Borla Exhaust, HKS EVC IV, HKS SS Blow Off Valve, Aluminum Flywheel, Underdrive Pully and HKS Timer, it has made the problem much worse. I'm in Colorado where mostly 91 octane is sold but we have less air. Also I have a friend with the same modifications as me using 91 octane with no problems. I have replaced the plugs and wires and ingition coils and neither has helped. My last guess is the computer but I don't want to spend the $ if that isn't it. Any help will be greatly apreciated.
 

·
Registered
Joined
·
3,985 Posts
Could be timming. Did you have the timing belt replaced? Maybe when they did it.. they didn't do timming correctly.. u should look into that..
 

·
Registered
Joined
·
653 Posts
How did you gap the plugs. I think most of the Gurus (Roger, et al) recommend .034 for increased boost. My car misfired badly under higher boost until a repaced the plugs with new ones gapped at .034.

Hope this helps.

Mike
 

·
Registered
Joined
·
1,276 Posts
I'd also look at the plugs and the gap. If you used any plug other than the NGK standard plugs this could be your problem. I tried a set of Bosch Platinum Plus 4's and they immediately caused hesitation problems. Went to a new set of NGK's and the VR4 runs perfectly.
Based on your mod's the plug gap will also be important, particularly with sub 93 octane gas.

Hope that helps.

Chris
 

·
Registered
Joined
·
1,276 Posts
One other thing. What did you use for plug wires? If you didn't use the factory wires (not great, but they work)or Magnecore wires (very good quality, well engineered, but expensive)this could also be the (or a part of)the problem. Many aftermarket wires are little more than color and hype. Claims of low resistance or special "capacitor" circuits are bogus nonsense that is marketing not electrical engineering.
If you have the factory original wires (and they are in good shape) try putting them back in to see if it helps.

Chris
 
C

·
Guest
Joined
·
0 Posts
Discussion Starter #7
Did it just start happening when you installed EVC, and does it only happen when boost is applied? I am not familar with the HKS, but on my GReddy Profec B it talks about overboost. I can't see it being your timing unless you messed with it.
 
4

·
Guest
Joined
·
0 Posts
Discussion Starter #8
It started a little bit before the mods then I installed the EVC, Intake and Exhaust at the same time. I changed the gap last night will try it today I really hope that was it.
 
4

·
Guest
Joined
·
0 Posts
Discussion Starter #9
I changed the gap to .034 and the car ran great for about 8 hours but it's doing it agian. I'm using the stock wires and plugs also just had the timing belt replaced ( 1500 miles ago). All I can think of is the computer. It's starts a little in third high rpm's then to second then first gears. No mitsubishi dealer has been able to tell me what the problem is.
 
J

·
Guest
Joined
·
0 Posts
Discussion Starter #11
Have you valve seals checked. Pull the two hoses on the y-pipe and see if you have oil
residue on inside wall of hose. This will cause you hesitation and more, trust me.
Also, does your car idle rough for a bit when you run it for a while, then stop for a few, then start it again? If so, then your answer is above. Bad valve seals was the diagnosis when I had that problem. Too bad it took the dealer 12 months to figure it out and then they put the head back together wrong, so now I have a brand spanking new front cylinder head. Watch those dealers!! They'll screw you!!
 
4

·
Guest
Joined
·
0 Posts
Discussion Starter #12
I don't seem to have any oil residue at least no more then would seem normal. I'm running out of ideas. I talked to the mechanic that replaced my timing belt and he said it was put on right. Is there a way I can double check it? If it was the timing belt why does it run ok for a day or so then run bad for a month?? Maybe vacuum hoses? Computer? Someone please help me figure this out.

[This message has been edited by 400hp 95 VR-4 Spyder (edited December 17, 1999).]
 

·
Registered
Joined
·
3,449 Posts
the only way to check the belt is the remove the plastic sprocket covers and look at the timing marks on the sprockets vs the timing marks on the valve cover vs the timing mark on the crank pulley. The marks should ALL be DEAD ON, not "close", but PERFECT. You want to put the car on TDC which is the first mark on the crank timing marker that looks like an "I", and match that up with the small mark on the crank pulley, then pull off the sprocket covers and look at those marks. The reason the car is inconsistant, is that the ECU is constantly trying to alter things becuase the car's timing is not dead on, and this will cause this problem. AMKREADGTO who is on this board, had this exact proble that you are desribing, and his "so-called" mechanic said the timing belt was put on correctly too, but his car ran like your's is running.
 

·
Registered
Joined
·
1,006 Posts
Cool Car, I want to build a 600 hp spyder, maybe in 2000. How does your car handle, stop etc? The spyders are quite a bit heavier than my 92 VR4.
Your hesitation sounds like your Y-pipe is blowing off, time to get an aftermarket 1 I would suggest
 

·
Registered
Joined
·
1,496 Posts
For what its worth, I think it is either the timing belt being off a tooth, plugs with too large a gap, or a weak fuel pump. try to check with a manual fuel pressure gauge to see if it is going lean under higher rpm / load.
 

·
Registered
Joined
·
2,057 Posts
My 2 cents, your mechanic may have been right, at first. But as the auto tensionor expanded it could have resulted in putting your timing marks off. It tells you in the shop manual that you pull the pin and wait 20 minutes for everything to tighten up and then check your marks again to make sure everything is line up right before putting it all back together. If your mechanic didn't wait and started to reassemble then there is a good chance things maybe slightly off, a tooth, like Brain said.

This is just a thought, it took me 3 trys to finally get everything lined up. I had to advance my crank shaft one tooth to insure everything lined up, as the auto tensionor expanded everything in the world lined up, just like it was susposed to. But again that was the first time I ever tried replacing a timing belt and these 3000 aren't the easiest things to learn on. I don't expect to have near the problem when I replace it at 120K.


Dave Best
3Si #62
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #17
At 60k after the 60K service my 91 VR4 hesitated and missed. Th mechanic had apparently broke a cable or sensor related to the throttle I think. They replaced it and all was fine. Could be the problem. Sorry I can't remember the details (3yrs ago)
 
4

·
Guest
Joined
·
0 Posts
Discussion Starter #18
I checked the timing belt and it's off 1 tooth. I take it back to the doctor on tuesday. The Spyder handles good and stops good. (not as well as a VR-4) My next upgrade is the brakes. With performance tires I'm happy with the handling for now. THANK EVERYONE FOR YOUR HELP! It's great we have a site like this with people so willing to help!!
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #19
I had the same problem after my timing belt
was changed at a mitsu dealership. On the
way home from the shop it hesitated a couple
times at cruise speed (70mph). After spending $1070. I expected the car to run better. Since I had to wait two weeks to
to have my car checked, and the maintenance manual finaly arrived I decided to do my own troubleshooting. While no fault codes were displayed I found the front O2 sensor to be bad. Replaced with a new one ($91) and problem solved.
 
1 - 19 of 19 Posts
Top