Rattling Noise when gas is pressed

I just posted in the welcome thread, so now I'm coming here with the issue that's on my mind, thus this is my first technical post.

I'm hearing a rattling noise as I have my foot on the gas in gear. It only happens when my foot's on the gas - it stops immediately as I lift my foot off of the pedal. It also only happens when I'm in gear and moving - if I try to rev it out of gear, it doesn't make the noise.

It's a metallic sound. It can best be described as the sound of wires scraping against something or cans scraping together.

It initially was only particularly audible in fifth gear at highway speeds. Today, however, I started to notice it while driving around town in lower gears. There are a few things that have changed recently. The temperature is noticably warmer today than it was the last time I drove it, a week or so ago. I've started to use regular gas recently, rather than the few tanks of premium with seafoam that I ran through it immediately after buying it. I changed my belts recently (and have hardly driven it in the few days since). I also just picked it up from my mechanic a few hours ago - he had changed my timing belt, water pump, radiator, and thermostat.

Given that it seems to be related to gas, I'm going to start out with changing the spark plugs, wires, distributor cap, and rotor.

Does anybody have any thoughts?

have the mechanic check the timing belt install - the belt may be one tooth advanced from where it should be. Refer to the threads on here on the correct install of the iming belt - people get it wrong all the time on these motors, although usually its 1 tooth retarded.

I took it back to the mechanic - he called it a spark knock, and told me to run through a tank or two of premium, and then bring it back to him if it was still doing it. He also adjusted the timing on the distributor, but that didn't really make much difference.

He said that it wasn't really anything to be concerned about, apart from it just being an obnoxious noise. I'm sure he'll check the timing belt if it's still pinging after using premium for a bit.

I'm still concerned about wear/damage to the engine, though, and to have to use premium all the time, whether I want to or not, would be a pain.

I second what pennyman says. He got it off 1 tooth. It's easy to do and EVERYBODY does the first time on these things. The rule of thumb is to line it up with the flat of the head, but that is retarded 1 tooth. It's most likely advanced at the crank by 1.
He probably didn't think anything about it when he pulled the distributer out and moved it one tooth to retard it to make it come back into timing. after changing the belt. Or there is a vacuum leek and it's lean like a mother and turning the header red hot.
The worst that can happen is you over heat it and crack the head or melt a piston or burn a valve.

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Head mark


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If he adjusted the distributor without grounding the ECU pin to put it in "Timing Mode" then take the truck to somebody else, he's doesn't know Mitsubishi's.

Maybe you just got a poor quality tank of gas. I just started having some serious pinging, right after I filled up with gas. I always use regular. Once I get down to a half tank. I plan on refilling with super. I will let you know how it turns out.

It will be interesting to see how a tank of premium, and then another tank of regular, do. It makes sense that the timing belt is likely off by one tooth. I'm thinking about teaching myself how to adjust the timing by the distributor using a timing light. One thing I'm wondering, though: if the belt itself is off by one, then would putting it back into proper timing by adjusting the distributor work? And if so, would that be a bad idea? I've also noticed another interesting correlation. The engine heat does go up by quite a bit while driving. It never goes into the red, but it does sometimes get rather close to the white line on the far right. I replaced the radiator, water pump, and thermostat, but it still does the same thing. I recently noticed, however, that the engine doesn't really ping when it's cold (just started up, temp gauge still on the far left), and it pings worse the warmer the engine gets. That leaves me with the interesting puzzle of why it's still overheating with a new radiator, water pump, and thermostat. I think that there's probably a correlation with the temp and the pinging, but I'm not sure which way it goes - whether it's pinging because the engine is getting so hot, whether it's getting so hot because it's pinging, or whether they're completely unrelated.

Oh, and apparently the editor ignores line breaks, so my text all ran together, and there doesn't appear to be an 'edit' feature O.o

Also, a note on the overheating - it's not consistent. When I'm driving around town, the temp does slowly go back down after hitting a high point. I haven't taken it on the highway since replacing the radiator/water pump/thermostat, but beforehand on the highway the temp would rise and stay there until I turned on the heat, at which point it would very slowly go back down to the middle.

if the timing is too advanced, it will run hot. Being 1 tooth off is more than you can adjust out by moving the distributor. You also may have an issue with the vacuum advance sticking in the distributor, causing the timing to stay advanced.

It ran perfectly fine on a tank of premium. No knocking, and the temp was fairly cool. I was impressed. Then I put some more regular in, and as predicted, it went right back to knocking and running hot.

Tonight I checked the timing with a timing light. I wanted to have a better idea of the timing situation before I go back to the shop that did my timing belt.

However, Haynes specified to ground the connector and the 'ignition timing adjusting connector', but I was unable to find it, so I did my check/adjustment without that connector being grounded.

Without having grounded that wire, the timing was around 15-20 BTDC. According to Haynes, it's supposed to be between 3 and 7 BTDC. I was able to bring it all the way back to 5 BTDC in my tinkering, but when I put it back together I left it at 10 BTDC because I don't know how accurate the reading is without that wire being grounded and because I'm not yet sure what's up with the timing belt, if anything.

I'll report back on how it drives over the next few days with the timing closer to the norm, but I had a few questions in the meantime. Where exactly is the connector that I'm supposed to ground, and how much of an effect would that have had on my reading? Also, what can you tell from the fact that the timing was 15-20 BTDC, and that I was able to bring it back down to 5 if I wanted to? Does that mean that the timing belt was installed correctly after all, and that I just need to adjust the distributor?

While driving to/from work and around town today, I no longer heard the signature spark knock sound. I did, however, notice that:
-It still runs just as hot as before, if not more so
-I'm lacking a noticable amount of power. I occasionally notice a very low rumbling idle, and I also occasionally need to give it more gas than I used to to keep it from chugging while driving around at low speed/gears.

The fact that I'm lacking power, in spite of the ignition timing still being further advanced than It should be, seems very odd to me. Shouldn't it be the other way around?

I also tried checking the vacuum advance, but I didn't see anything that resembled the vacuum advance pictured by Haynes on the distributor. Is this particular model supposed to have a vacuum advance?

Here are some pictures of my distributor in case that helps with the vacuum advance:

From the top/front:
Attachment 14166

From the bottom/front:
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From the top/left:
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To much advance will make an engine run hot. So does a vacuum leak. The brake booster is notorious for hiding vacuum leaks. Sometimes are there sometimes they're not.

Just to mark this with a conclusion, there was a happy ending to this story.

It turns out that there were actually two things going on:
-The timing belt was, in fact, off by a tooth, as predicted.
-The thermostat was shot

When I took it apart to replace the timing belt, it was obvious that it was misaligned, although it was still knocking after I got everything back together. Then I took the thermostat out entirely, and the knocking stopped almost at once.

I then carried a wrench around with me for the next few weeks. Every time I noticed that the timing was too far ahead or behind, I'd stop, get out, and adjust the distributor very slightly, until it was running properly. Then, when I put in a new thermostat, everything continued to run with no problems.

It seems odd to me that the thermostat was bad, considering that it was a new one. I'm guessing that either it was bad to begin with or it got burnt up as a result of the timing being too far advanced (which itself was a result of the timing belt being off by a tooth).

you got to love theses little trucks the way they make you think lol