help with 3.4 dohc

[javcr]

Hi all

The last two days i have been trying to get my montecarlo 3.4 dohc running fine, i change the timming belt , i double check the timming, changed spark plugs , new air filter , all vacuum lines checked and the idle continues very erratic, it looks like the cilinders 1, 5 and 6 are not working but the injectors seem working and i have checked the wires and looks good, to much fuel odor on the exhaust (when i pull the ignition wire there are no change) i take it to the shop for scan and just have the codes for oxigen sensor low response and pt low response, when i drive it to the shop on high rpms about 2000 to 4000 run good with good power
any help
Javcr

[3100 MPFI]

pulling the spark plug wires, and no change means either no spark, or no fuel.

First, what YEAR monte carlo are you working on? 1995 will have the older 3.4 DOHC, and 1996, and 1997 will have the newer 3.4 DOHC.
Second, which spark plugs did you use, and did you gap them properly?

[bve32k]

Is the MAF plugged in?

[javcr]

thanks for your replay,
the montecarlo is 1995, 3.4 dohc, this idle failure is maybe three or four months thats why i am working on it, i replace the old spark plugs with new platinum two electrodes plugs, when i pull the wires on the 1, 5 and 6 there are no changes and can ear and see the spark, about the fuel just check the exhaust and smell to much fuel whitout burn, today i checked again the fuel system and show 41 psi steady , about the MAF, i unplugged the conector and the rpms rise from 600 to 1200 but still the engine is vibrating, when the conector is plugged the engine quit, just run steady passing 3,000 rpm and i think is correct when i give full throtle the engine stop rising at 4000 rpms , again i checked with scanner and the same o2 sensor low response, pt sensor low response, and now MAF low levels, maybe because i have been running the engine with the MAF unplugged, what do you think that i have to do?
i checked with a local mechanic here and he want to overhaul the engine at very high money i know a little of this kind of engines but i dont think that need overhaul..no oil smoke, no noise, good power etc
Thanks in advance

[pocket-rocket]

Well two electrode plugs says Bosch +2's to me. Get yourself 6 AC Delco plugs and toss those in there. The waste spark ignition system on these cars do not like Bosch plugs. Then go from there

[55trucker]

Did you have this problem Before you changed the timing belt?....try looking at this thread....sounds verrry similar to what you are suffering from....http://www.clubgp.com/newforum/tm.as...mode=1&smode=1

[3100 MPFI]

all bosch plugs are crap. Just get the delco ones. And make sure you gap them. Those bosch ones, you don't set the gap on them, so if it is not right, that alone can cause a problem. I also don't like to use platinums. I just put 4 new plugs in my twin cam. I got the DELCO R44LTSM No problem with them at all.

Replace the plugs, and try again. If it still does it, we need to look at either fuel, or something with the coil packs, and DIS.

1, 5, and 6 are on 3 different coil packs. The coils are 1 and 4, 6 and 3, 2 and 5. Seeing that it is one from each coil, the chances that ALL THREE COILS went bad is very remote. I would say the DIS itself, if it is not just the plugs, or maybe a timing issue.

I think if it was timing, it would effect either the complete fronts (2 4 6), or the complete REARS (1 3 5) and not 2 rears, and a front.

[pocket-rocket]

all bosch plugs are crap.

That's funny, because the other day while I was at the parts store (Advance) I was telling the manager that was helping me about my ignition system not liking Bosch plugs while I was checking the price of Iridiums. He said corporate had commented to him that he's not selling many Bosch plugs and his reply to corporate was "Because Bosch plugs suck, and I am not going to sell junk to my customers!" I got a laugh from it, lol.

[javcr]

Hi all thanks for your time,today on the morning i changed the spark plugs again with delco, the same, i have cleaning the injector with ultrasonic cleaner , install them and the same, and on response about the failure, yes, was there before change the timming belt, thats why start to work first with the timming belt because i see it very old,... on this afternoon i have again the car on the shop for scanner and with the help with the technical, he check maf, o2, knock sensor, timming, spark plugs, wires , and try with different coil packs, and the same, tomorrow i will send the ecm to check just in case..

[javcr]

hi 55trucker thanks for the link, when i changed the timming belt the tensioner have not oil, maybe the spring have not enought pressure anymore, i will try changed the tensioner, right now i will order a new one

[deansharkgp]

That was my post over on clubgp. I was going CRAZY with the thing. Had to be 4-5 months, I was changing everything and nothing worked. I was so stumped that I brought it to the dealer. Within an hour they called me back and told me what it was. Luckilly they changed it when they did the timing belt so the repair was all on them. But anyway, I would 99% guarantee that your problem is the timing belt tensioner. My suggestion is, while your in there, change all the pullys and everything. I hate to say it but it should have been changed the first time when you changed the belt. Some times it is cheaper to spend more money the first time you do something then you won't have to spend the time taking it apart again. Good luck with it.