VE3HZZ Posted September 29, 2011 Share Posted September 29, 2011 Ok so I just got my Monty and it has an annoying habit I need help to decipher from those who've been there and done that so I don't chase my tail. When I stop at a light the car will idle REAL low and lope (cam) and stall. If I put it in neutral it will idle low but stay running. I am thinking it has to do with timing and the vacuum as it is being robbed by the brakes possibly. I need to go through it. Some background it is not the Original engine it is a 350 with a rebuilt 350 transmission and a Quad 4bbl and has headers with dual exhaust that I think do not cross over, straight to back (need to confirm this when it stops raining out.. I don't have a timing light (have not had need for one in years) so need to buy a good one soon. So my question is what have others who've experienced this done and fixed the problem. I know I am not the first to have this issue, but some directed advice from those who have would be very much appreciated. If it was someone elses car I could diagnose the problem in moments..but my own...to close to it??? not the perspective of an observer? So any help in this department would help me greatly. Thanks and anytime I can return the advice I'll try to chime in. Regards Scott Quote Link to comment Share on other sites More sharing options...
stangeba Posted September 30, 2011 Share Posted September 30, 2011 Scott, If you have power brakes, here is a quick test to see if your problem could be related to a vacuum leak (rare) in the brake booster. To accomplish this. you need a properly working parking brake. If you have never used it, be careful because it may be frozen and won't release. If it's good then apply the parking brake then put it into D and see how it idles. Then apply the foot brake and see if it gets worse. If it does, you probably have a vacuum leak in the power brake booster. If it is the same, set the idle up a bit higher and start looking for other vacuum leaks on hoses. Bruce Quote Link to comment Share on other sites More sharing options...
robs70monte Posted September 30, 2011 Share Posted September 30, 2011 You could unhook the hose at the booster and put a big vacuum cap on it and hop in it fire it up and put it in drive and hold the brake if the problem is one its the booster Quote Link to comment Share on other sites More sharing options...
VE3HZZ Posted September 30, 2011 Author Share Posted September 30, 2011 Thanks I will give that a try. It was just saftied and the emergency brake was tested and found to be working fine from the report. Excellent idea I likely would not have thought of that in this case. Regards Scott Quote Link to comment Share on other sites More sharing options...
VE3HZZ Posted September 30, 2011 Author Share Posted September 30, 2011 Another good suggestion. Thank you keep em coming I want this issue resolved so Monty and me can have a nice cruise (if it will stop raining) this weekend!!! Regards Scott Quote Link to comment Share on other sites More sharing options...
stangeba Posted September 30, 2011 Share Posted September 30, 2011 What trans? If it has a newer Overdrive 200 4R or 700 R4, the lock up torque converter may not be unlocking? Bruce Quote Link to comment Share on other sites More sharing options...
TrunkMatt Posted October 1, 2011 Share Posted October 1, 2011 Quick fix: You can also try running your vacuum advance to your distributer off the manifold vacuum and see if that helps keeps the timing advanced enough... if it does & things work better you know you have a weak vacuum off the other port & your timing is a bit off. I used to have this problem on my Qjet where the vacuum was low. It was my Quadrajet ports & vacuum leak. It needed a rebuild... it happens when the internal plug holes are not sealed correctly and you get some internal leaks when idling when warm at stoplights etc. While I opened up my Qjet for repair I put an Edelbrock 650 performer on and it went away... and idles a lot smoother... so I left it off. I love the power of the Qjets though. You probably need a carb cleaning / needles adjusted for idle / and a complete rebuild of it. Should be between $100 - $200 at a good rebuilder of Q Jets. Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted October 1, 2011 Share Posted October 1, 2011 Heres a simple minded question from a simple minded person but what is your idle set at? maybe it just needs to be bumped up a bit. Maybe I missed something I didnt see that asked. Quote Link to comment Share on other sites More sharing options...
TrunkMatt Posted October 1, 2011 Share Posted October 1, 2011 You make a good point... I guess we are assuming the idle is set correctly based on his knowledge that he posted. But, yeah - it Could just be an idle speed adjustment. What RPM is it idling at in Neutral / Park?? Do you have Tachometer?? Depending on your cam you should be between 800-1000 rpm in park neutral, and 600-750 in gear with brakes on. I like mine at 975 in neutral and 700 in gear... but I have a cam that needs a bt more idle. Quote Link to comment Share on other sites More sharing options...
VE3HZZ Posted October 1, 2011 Author Share Posted October 1, 2011 Thanks for all the replies so far. To be honest, I think it is a TH350 don't know what the stall is nor for that matter what cam is in it for any numbers. No tach as of yet to check idle. But I would hazard to guess in Neutral/Park it is running 800 and when in gear and foot on brake it is like 600 or LESS which is causing it to stall. All good points that tomorrow I plan on looking into. Due to my time off work and it's getting dark out fast I've put off doing anything till tomorrow when I have SUN and time to look at it and fiddle with it. I litterally drove it home last Saturday and a bit around town on Sunday and it's been parked with the cover on it all week!!!! So tomorrow I will try some of the suggestions on here for diagnosis and see what I come up with. I wouldn't put it past being the timing AND vacuum both!! I will try to do my best to get to the bottom of this. I do appreciate all the comments and suggestions so far and I also need to crawl under it and pull some numbers from the engine, transmission and rear axle so I can be better informed as to what it should have and what was done. It is not that anything is done wrong, I don't know what it is so in the dark so far?? But I will find it with all the great help and tons of experience from my new Monty family Regards Scott Quote Link to comment Share on other sites More sharing options...
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