Red line. I know what you mean not wanting to rev it up not under load. Just do it slowly. I don't think it would be bad to rev it from the throttle body but it also wouldn't hurt to have someone help you.

__________________
William Weatherby

Red Line? You mean to rev it to 6000 RPM without being under load is not bad for it. I never went past 2000 RPM unloaded and today I was driving around in 3rd and getting the Tach to 4400 and did not think that was healthy.

I know in manual trannyd cars you can get close to red line , but I was always afraid it would cause a lot of heat in lower gears on an auto tranny.

So you think both practices are safe, and I am just babying my cars too much ?

I drove today and after 3-4 engine turn ons/off I got the hesitation again and it nearly died on me during one of the restarts. Grrr

By the way I was in the country last night where it was dark, and wanted to check for arcing before I came home, but I got into a conversation about something and forgot GRRRR.

In any event the caps and rotors are here and the mechanic said to bring it in to replace them tomorrow/thursday . I notice that the Bosch parts I bought from the internet were made in Spain . Hope they are as good as OEM .

Will change caps/rotors and drive around for enuff time to heat engine up and see if the hesitation/dying is cured. If not MAF cleaning is next and then finally plug wires.


I will post my progress for anyone following the thread.

Thanks again for all the comments

Actually, you don't need to rev the engine at all. You'll be able to see and hear the arcing with the car at idle. Try it, you'll see.
Regards, Eric

__________________
89 300E "Benzer1" 15.924 Uncorrected
93 400E "Benzer3" 14.200 U.C.
95 E420 "Benzer4"
92 300E "Benzer5" 16.299 U.C. Future turbo CNG
87 300D "Benzer7"
87 300D "Benzer8"
87 300D "Benzer9"
87 300D/70 AMC Javelin "Sidewinder-Benzer"
87 300TD "Benzer11"
06 E320 CDI "Benzer12"
05 E320 CDI "Benzer12A"
71 AMC Javelin AMX 401 "Sidewinder"
74 AMC Hornet 401 "C.K.10" 13.63 U.C.
74 Bricklin SV1 "Presto" AMC 360 pwrd.

He's right. Actually, at lower RPMs the spark should be stronger and show more where it's arcing.

I probably wouldn't red-line it in neutral. Something just seems dangerous about that. I don't know what the difference would be though.

__________________
William Weatherby

Is it OK to look at it immediately after start up? Or should I wait till it starts to hesitate/bogg down that happens after its warm, and it gets worse with every additional turn off /restart. Then after 3-4 restarts even the idle breaks up and almost stalls like I said in post #32 above.

If its not doing its crazy thing , would the arcing be happening , or only when it has symptoms?

If you can replicate the symptom then that's what you should do. Maybe check it when it's cold and running fine and also later when it's warmed up and running worse. Are you getting your cap and rotor on today? Remember to save the old one.

__________________
William Weatherby

When you say check it, do you mean look for the arcing ?

Well today I drove 25 miles on a highway ( LIE) to go change caps/rotors. Got caught in traffic for the last 10 miles so engine got to around 98 C (I Use K6JRF a/c diagnostics to display engine temp in a/c window) and it missfired pretty hard 2-3 X. Actually sounded like a backfire .

Got to the mechanic who swore without seeing car that it was caps and rotors that were the problem. He changed them and said the old ones were bad. I took them with me to look at . Dont ask me what I am looking for , but you can tell me what to look for ,and he said they were bad.

Drove the car all around long island for 30 minutes and it hesitated a few times but for a much shorter duration and less frequently than before , at least in my mind thats what I thought.

I drove back to the new Mechanic and told him it is better but still not right. He said its not the MAF, as I had that in mind to work on next . He says it prolly is the suppressors on the spark plugs. I told him I should change wires totally and he said just change suppressors. I told him his ex boss at MB dealership , who is shop foreman of mechanics, changed 3 suppressors and said if that did not solve it, plus changing all the plugs that the dealer did, I should change wires next . New mechanic said wires in my model car do not go bad. Grrr . Opinions

The new mechanic said also to change fuel filter when I change wires, to protect against bad gas . I might just change filter and give that a shot before I spend $$ money on wires. Does anyone think that could be the cause ?

I thought maybe give the sensors time to acclimate to the new rotors and it seemed better for a about and hour in stop and go, start and restart. After 45 minutes driving I accellerated quickly from a toll station and it stalled for a fraction of a second as opposed to 1-2 seconds as before.

Then I got into NYC and drove around in traffic and the hesitation although "MAYBE" not as severe is still there . Obviously the car gets warmer in NYC traffic and thats where I really have to be able to have the car run perfectly, to say it is fixed.

It looks like this is becoming a parts changing , guessing game for me .
I thought I would do the MAf cleaning but this mechanic says that stuff is garbage . So many mechanics, so much disagreement .

I am going to look tomorrow night at the wires to see if they are arcing and MAYBE disregard what he says and do a MAF cleaning . Or I could just change the fuel filter, unless I have an obvious arcing that I can see .

Again the problem happens and gets more frequent the warmer the engine is . Grr .Is there no way to diagnose this problem without just changing parts arbitrarily? He did not put a diagnostic tool on the car and I will call him tomorrow and ask him why not .

What should I look for on Caps /rotors? I am getting a daily headache from this.

The only good news is that this guy is very fair, pricewise and seems very honest .

Any other thoughts guys. I am going to take 2 tylenol .

Caps and rotors done today. That was not the problem. Plug wires the only other candidate in your opinion?

For an engine to run properly, it needs three things.
1. Good compressing in each cylinder.
2. A good spark at the right time in each cylinder.
3. A good air/fuel ratio and volume flowing into each cylinder.

1. Compression tests and leak down tests are easy to do and cheep. Do it with the engine warm.
2. New cap and rotor is good, wires should be tested, you're about to do that.
3. A number of things on a modern engine could throw off the air/fuel ratio.

Don't give up. It usually turns out to be something simple that makes an engine not run right.

Could you post photos of the caps and rotors? Then we can tell you what we think of them.

Plug wires that "leak" spark before it gets to the plugs could be your problem.

__________________
William Weatherby

Yes I can take photos. How do I post them to a thread .
I never did that before.


Also frustating is that car almost always runs well when cold(er). Also that once past 1400-1800 RPM it runs well and once I am on the road and doing 60-80 MPH it feels fine.

But I guess when I am doing 60-80 the engine temp drops back to under 50C so, that sorta explains that.

What do you think about replacing fuel filter before jumping in and replacing plug wires?

I personally have not checked all the vacuum lines but 2 mercedes benz mechanics, including the first one spending 2 hours diagnosing it , I find it difficult to think that was overlooked.

Also the first mechanic who is still working for the dealer said the next thing on his list to change would be plug wires , so I guess I should bite the bullet after checking tomorrow night to see if there is any arcing

When you say check it, do you mean look for the arcing ?

Well today I drove 25 miles on a highway ( LIE) to go change caps/rotors. Got caught in traffic for the last 10 miles so engine got to around 98 C (I Use K6JRF a/c diagnostics to display engine temp in a/c window) and it missfired pretty hard 2-3 X. Actually sounded like a backfire .

Got to the mechanic who swore without seeing car that it was caps and rotors that were the problem. He changed them and said the old ones were bad. I took them with me to look at . Dont ask me what I am looking for , but you can tell me what to look for ,and he said they were bad.

Drove the car all around long island for 30 minutes and it hesitated a few times but for a much shorter duration and less frequently than before , at least in my mind thats what I thought.

I drove back to the new Mechanic and told him it is better but still not right. He said its not the MAF, as I had that in mind to work on next . He says it prolly is the suppressors on the spark plugs. I told him I should change wires totally and he said just change suppressors. I told him his ex boss at MB dealership , who is shop foreman of mechanics, changed 3 suppressors and said if that did not solve it, plus changing all the plugs that the dealer did, I should change wires next . New mechanic said wires in my model car do not go bad. Grrr . Opinions

The new mechanic said also to change fuel filter when I change wires, to protect against bad gas . I might just change filter and give that a shot before I spend $$ money on wires. Does anyone think that could be the cause ?

I thought maybe give the sensors time to acclimate to the new rotors and it seemed better for a about and hour in stop and go, start and restart. After 45 minutes driving I accellerated quickly from a toll station and it stalled for a fraction of a second as opposed to 1-2 seconds as before.

Then I got into NYC and drove around in traffic and the hesitation although "MAYBE" not as severe is still there . Obviously the car gets warmer in NYC traffic and thats where I really have to be able to have the car run perfectly, to say it is fixed.

It looks like this is becoming a parts changing , guessing game for me .
I thought I would do the MAf cleaning but this mechanic says that stuff is garbage . So many mechanics, so much disagreement .

I am going to look tomorrow night at the wires to see if they are arcing and MAYBE disregard what he says and do a MAF cleaning . Or I could just change the fuel filter, unless I have an obvious arcing that I can see .

Again the problem happens and gets more frequent the warmer the engine is . Grr .Is there no way to diagnose this problem without just changing parts arbitrarily? He did not put a diagnostic tool on the car and I will call him tomorrow and ask him why not .

What should I look for on Caps /rotors? I am getting a daily headache from this.

The only good news is that this guy is very fair, pricewise and seems very honest .

Any other thoughts guys. I am going to take 2 tylenol .

Test for arcing already!
You'll be able to see some arcing even during the times when you are not experiencing symptoms.
Regards, Eric

__________________
89 300E "Benzer1" 15.924 Uncorrected
93 400E "Benzer3" 14.200 U.C.
95 E420 "Benzer4"
92 300E "Benzer5" 16.299 U.C. Future turbo CNG
87 300D "Benzer7"
87 300D "Benzer8"
87 300D "Benzer9"
87 300D/70 AMC Javelin "Sidewinder-Benzer"
87 300TD "Benzer11"
06 E320 CDI "Benzer12"
05 E320 CDI "Benzer12A"
71 AMC Javelin AMX 401 "Sidewinder"
74 AMC Hornet 401 "C.K.10" 13.63 U.C.
74 Bricklin SV1 "Presto" AMC 360 pwrd.

Yes, test for arcing.
To post a photo in a reply to thread, click on the little yellowish box that looks like mountains.

__________________
William Weatherby

No, arching not arcing. I'm talking about little men under the hood with little bows shooting little arrows! Hence the term: arching.

(Just kidding. Seems I've been having a brain fart on my spelling lately.)
Regards, Eric

__________________
89 300E "Benzer1" 15.924 Uncorrected
93 400E "Benzer3" 14.200 U.C.
95 E420 "Benzer4"
92 300E "Benzer5" 16.299 U.C. Future turbo CNG
87 300D "Benzer7"
87 300D "Benzer8"
87 300D "Benzer9"
87 300D/70 AMC Javelin "Sidewinder-Benzer"
87 300TD "Benzer11"
06 E320 CDI "Benzer12"
05 E320 CDI "Benzer12A"
71 AMC Javelin AMX 401 "Sidewinder"
74 AMC Hornet 401 "C.K.10" 13.63 U.C.
74 Bricklin SV1 "Presto" AMC 360 pwrd.

I will be testing for the Olympic Sport Arching or is it Archery tonight Then I have to dig out my camera and take the photos of caps and rotors . Thanks guys for all your patience