Today Matt95_GS and i did a full datalog and diagnostic check on my car. With the recent hesitation and just shitty acceleration we figured that it was something along the lines of a sensor or possibly the timing because of the higher compression. We ran the datalogger off of my roommates laptop and came up with one or two things.

First: My coolant tempurature was 220 degrees at the highest, which made the car run absolutely horrible. From what Matt says, normal operating temps are around 207. We drained most of the coolant and added more water to try and compensate. Now, my radiator cap is rated at 13 lbs, not 16 like matt has on his car, could this cause the temp to rise like that?

Second: Seems normal now, but we checked the tps percentage at WOT and it only opens 78% of the way. Shouldnt the tps read 100 percent at WOT?

Third: My ecu. With the car only hesitating and popping under a load, is there a possibility that when the car is under a heavy load the ecu will freak out and possibly start making the car run like it is? I understand that everything boils down to voltage in the ecu, so what we were thinking is once the voltage gets too high, or the ecu gets heat soaked, it starts to short out. Im in the process of ordering a used ecu, so hopefully within the week i can figure this one out.

Other than that there is nothing wrong with my motor. We are just stumped. Is there anything else i can check for, or more information needed to dianose anything else?

>First: My coolant tempurature was 220 degrees at the highest,
>which made the car run absolutely horrible. From what Matt
>says, normal operating temps are around 207. We drained most
>of the coolant and added more water to try and compensate.
>Now, my radiator cap is rated at 13 lbs, not 16 like matt has
>on his car, could this cause the temp to rise like that?

Have you totally flushed the coolant system?

twice

could it be ingnition? i have the same probs for a long time actually. the next thigns to go on my car is fuel filter, coil, 02 sensor. in that order cuz i'm cheap ;)

Everything ignition wise checked out. Im leaning towards the ecu, i just paypal'd someone for a used ecu. Hopefully this will cure my car. Any other tips??

Eliminating the ECU as a variable will clear it up. Have you tried a higher pressure cap for the radiator?

I havent tried another cap for the radiator, if the problem persists i will buy the 16lb cap. As for the ecu, there isnt very much more i can do after that. Matt had the idea that my timing is off by a few degrees, but we really cant mess with it because i dont have cam gears. This is something i'll look into "if" the ecu doesnt work. Any other tips??

As long as the plugs/wires are new...I would probably read the plugs and check the coil resistance. Maybe try a fuel injection cleaner if ignition seems to check out.


95 Eclipse RS : 5 speed
15.901 @ 88.34mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

The plugs are tan on the bottom. Ive had them for two days and they are the deep rust color, and from what i understand this means im running a little rich. The spark advance seemed fine, i really dont think its the coil. I bought my injectors with 38k miles on them and ive run several bottles of injector cleaner since the install. Anything else?

Have you done a compression test??

not recently..didnt even think about that

what about your cam gear timing? Did you ever get those adjustable gears?
What you are describing of how your spark plugs look, doesnt sound right. It should not be a rust color. Proper burn in the cylinders should result in the center insulator on the spark plug to be a tanish, white color. If its pure white, then thats running lean, and if its black and sooty, then its rich. If you can get pics of the plugs up on here, that can help. Also, you say it backfires? From the intake, or out the exaust? Does it only run like this under a load, or what? A compression test will just verify that you dont have any head gasket issues, or valve train issues. If you want, you may want to pull your valve cover and check out your valvetrain, esp the rocker arms. Just to rule that out. I always like to rule out major mechanical parts before i even think about electronic problems. Also, measure your voltage at the battery when you are driving when this happens, or at least when the car is running. No less than 13.4 volts

With the timing, Matt thought about it and decided that the problem just didnt seem like it could be timing related. The car only does this once its warmed up. I will try to get a picture of the plugs, but i doubt i will have the time or a camera to do so.

Now with the backfiring, it came from the exhaust. Its only done it a few times in the past week, but its been running extremely bad when it backfires.

The car only hesitates while under a load. We figured that when the computer see's the load it just freaks out and starts to malfunction. I would like to do a compression test tho, just to see if thats it.

I have inspected the valve train in the last two weeks. This was one of the first things i ruled out.

As for measuring the battery, i'll try that today.

Thanks for the responses and bring on a few more!

The only reason that I was thinking timing was because he had the head milled 50 thousandths when he got his headgasket changed. I know that will advance both cams some, but if the timing was set properly, I don't think it would be enough to cause what is happening. Also, if the problem was cam timing, wouldn't it run shitty all the time and not just when the car gets warmed up. It gets progressively worse the more you drive the car. Using the datalogger on the highway, the coolant temp slowly went from 208 to over 220 and it looked to me like if we hadn't got off the highway, it would have kept creeping up. I noticed that the higher the coolant temp got, the worse the car would run also. Normally though, when the car is overheating by that amount, I wouldn't think that would cause such a hesitation. This is by far the strangest problem I have come across so far which makes me think it's the ECU.

I had a bad hesitation problem to it to mitsubishi and they put it on the computer and could find absolutely nothing,but they were willing to start repalcing shit like it was on fire, anyway, it turns out it was my camshaft postition sensor, it wasnt bad or rather just bad enough to make my car tun like shit and replacing it fixed my problem

Well i made the trek home today..2 and half hours. All i have to say is that the car is running much better than before, but it comes with a price. I have to baby the car, shifting below 3k rpms, but i didnt have a problem the entire day while driving. I think changing the mixture of coolant helped out a lot. I have two days until my ecu comes in the mail so we'll have to wait and see if it works out.

Since my rebuild with the milled head and the adjustable cam gears, you can get some weird results by timing being off, especially on the exhaust side. I come up with a few bad timing setting s while playing around. So it could easily be the need for adjustable cam gears.

I would get the radiator cap taken care, back up to the stock 16psi
And get a set of adjustable cam gears and set the timing back to base
The ECU could be the culprit as well.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

Well heres another thing i figured out today. When the temps are cooler out(night) the car runs MUCH better than during the hot days. Im not really sure what it means but i has to mean something.

I replaced the radiator cap today and the car runs a bit better..who knows why though.

I higher pressure cap keeps more pressur ein the system, which keeps the coolant circulating better. Which has lower temps for the ECU to set fuel and timing curves off of. The ECU will pull timing adjust fuel, to prevent detonation and make sure the engine is safe.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

Well during the hot day yesterday, the car still had the missfire action going on. Later that night i was cruising with a few cars and my car was very peppy. I power shifted to second and burnt the tires a bit..which hasnt happened in a while:thumbsup Im thinking i need the adjustable gears and i might be set after that. The ecu i have coming is for a 96 so its not gonna work, so im going to have to try something else for the time being.