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Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8598
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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Mitsubishi Eclipse Spyder GT: We have been fighting an issue

Customer Question

We have been fighting an issue on our 2002 Mitsubishi Eclipse Spyder 3.0L where the car will not accelerate over 3000 RPM when in gear. We are not getting any check engine lights. We have replace a number of items trying to get this car legal: water pump, all of the belts including timing, both front O2 sensors and distributor. Driving slowly in the neighborhood the car is fine, but as soon as we turn onto the highway and try to accelerate the car will not RPM pass 3000. I'm out of ideas of what could cause this.
Submitted: 2 years ago.
Category: Mitsubishi
Expert:  Doug replied 2 years ago.
If you are certain that your belt timing is correct and distributor output is good (no weak spark... probably not an issue with a new distributor), your only real expectations here would be low compression (from other means than belt timing), a clog in the exhaust or low fuel pressure.
What I would do at this point would be first check to see if the exhaust at the tail pipe seems rather weak in flow when compared to another vehicle. This is a strong indication of a restricted exhaust.
Second I would run the engine up to operating temperature late in the afternoon/early evening as it starts getting dark outside. Then while it is idling/revving alternately, watch under the engine to see if any of the three converters are starting to glow. This is another strong indication of a clogged exhaust.
If nothing obvious is identified there I would move on to tool-required inspections... starting with a fuel pressure test while running (inline tester required) to make sure you have adequate fuel pressure (40's at idle, 50's with throttle snapped open) and NOT excessively higher either.
If pressure is OK, I would proceed to compression testing... which will require pulling the intake manifold to test all cylinders. Hopefully it does not go that far, as of course that is a good bit of work just for testing.
If however you get that far and compression is fine too (~120 psi range, and all cylinder within 10% of each other).... then I would circle back to the exhaust and perhaps try detaching first the mid pipe/rear catalyst and comparing behavior, then the pre-cats as last resort to try to rule out a clog.
Realistically... with the distributor and timing belt position already ruled out, it is very likely to be a clog in the rear catalyst. It is somewhat common to clog causing this behavior. The timing belt position and distributor (ignition coil inside it specifically) are far more common, but of course ruled out at this point in your case.
Customer: replied 2 years ago.
Thank you for your reply, I do believe the timing is in time, but this issue did not occur before I made these new changes. Could I of done something to clog the catalyst? It seems odd that in the garage in idle I can rev the engine as high I want to, but in gear I can only get up to 3000 RPM. Would the catalyst do that? I'm assuming once it's in gear things are under more stress but why doesn't it show this same behavior in idle too?
Expert:  Doug replied 2 years ago.
No problem.
The difference between in or out of gear is the amount of load on the engine. In neutral there is nearly zero load and it makes a huge difference regarding revving the engine when a problem is present.
It sounds like I may have misunderstood your original post. I had interpreted that you changed the timing belt trying to correct this issue... If that is incorrect and the problem developed after you changed the timing belt as your last reply sorry of sounds like, then disregard everything above and immediately go back to the timing belt.
As I mentioned before the timing belt position is far more likely to cause an issue like this just in general... If it ran fine before a timing belt install and like this afterward, that is pretty much a guarantee either the belt is out of time or the crank reluctor is out of time (behind the crank gear, the blade needs to be timed to the gear).
Customer: replied 2 years ago.
Thank you for all the information, I've spent the day today ripping the car apart again checking everything. The timing marks all appear to be in line with each other. Two questions, how do I tell if the crank reluctor is out of time? I'm assuming this is the plate behind the crank gear where the top dead sensor is mounted. Second, could the top dead sensor cause any of the issues we are experiencing? I found a crack in the sensor.
Expert:  Doug replied 2 years ago.
No problem.
The crank reluctor is behind the crank gear and will have a small notch in it. This aligns to the tooth with the dimple on the crank gear.
The crack in the crank sensor is definitely a concern, but it is also worth noting that if the crank sensor is broken, the car will not run at all.
Here is a photo of the reluctor and crank gear agreement. Note that the belt is not timed in the photo... it is just there to show the gear and reluctor agreement.

Customer: replied 2 years ago.
I've attached some photos of the car, could you take a look and tell if you can tell if this is out of time?
Expert:  Doug replied 2 years ago.
Those look dead on the money. How are the cam marks?
Also can you get a photo of the belt tensioner position?
I may be stepping out on a break shortly; if we miss each other I will catch up with you shortly.
Customer: replied 2 years ago.
Expert:  Doug replied 2 years ago.
Your marks look good however your tensioner is WAAAAY off. I'm not sure if this is going to cause an issue with regard to power... usually it causes an issue with the belt jumping honestly. Either way, you have got to fix that immediately... it is super tight and if it jumps you could wreck that engine.
Use my drawing below and match your engine to it so that it looks exactly like that after two hand rotations of the engine. Rotate the mechanical tensioner anti-clockwise against the belt when adjusting it.

Customer: replied 2 years ago.
I glad you caught that! I'm not sure how I did that, but would that cause an issue with the acceleration or is this something I need to fix?
Expert:  Doug replied 2 years ago.
I'm not sure if it is going to correct your power issue or not. The belt is SUPER tight from the looks of it which is not ideal of course, and you may find when it is adjusted correctly that it is a tooth off (since the tensioner is so far down, it might be off).
You NEED to fix this regardless... like RIGHT NOW. If that belt fails (jumps or breaks) due to the incorrect tension, you will be motor shopping.
Customer: replied 2 years ago.
I was finally able to put the car back together last night with everything in check, but the car is having the exact same issue. Once we put the car under load and try getting above 3000 rpm, the car will not accelerate properly. Going with the initial thought of timing, what else on the timing would cause this? Distributor maybe?
Expert:  Doug replied 2 years ago.
I wasn't too much expecting a resolution over that unless you found it was off a tooth once adjusted right, as I mentioned before that needed to be addressed as a priority for safety reasons more than anything... you were dangerously out of adjustment.
The distributors are prone to failure lately on these as they have been aging. Generally you will have a pretty distinct orange spark when this happens... is your spark weak like that or blue/white?
Regarding the timing... the reluctor blade on the crank gear would be the only other timing related suspicion I would have, but you look like you are in good shape in that respect.
Customer: replied 2 years ago.
Hi, I put new plugs, wires and distributor on the car. Put those on a few weeks ago. What concerns me with the distributor is it will not turn when as it should when you adjust. Is this common?
Expert:  Doug replied 2 years ago.
Can you clarify what you mean about the distributor turning? If you mean for adjustment like on an old 80's car distributor, these are not adjustable at all.
Customer: replied 2 years ago.
Ok, good to know. I referring to the 80's adjustment.I believe everything is in time, so I'm at a loss as to what else to check.
Expert:  Doug replied 2 years ago.
Right, no adjustment (one of the mounting holes is not slotted).
Did you ever try unhooking the exhaust at least before the rear cat and comparing behavior, if not at the headers (pre-cats) to see if the exhaust is causing any issue?

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