This is topic detonation problems...i think in forum Tech Talk at Northern California Ford Owners .
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Posted by robs2000gt (Member # 323) on
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I am thinking it is the plugs so i ordered some more. I run NGK TR-6 plugs gapped at .035. The car has a very rough idle when it is cold and it seems to be detonating in the top of 3rd and 4th gear. The idle was fine after the tune, but it just started back up in about the last 1-2 months or so. Do you think its the plugs or something else? Do you suggest trying some higher octance fuel mix or dumping torco in? The fuel pressure seems to be holding up fine. The plugs have about 5,000 miles on them. My tuner thinks the problem is from a vacuum leak. I dont think it is, plus the car is showing about 24-26 on the vacuum gauge at idle. I am not positive it is detonation but it does sound simliar to it. I am not sure what could make this happen since my tune because i havent changed anything. Can any help me or offer any suggestions??? I am running the stock 3.60 pulley with a AFM powerpipe, thats how i am getting 11psi. Thanks!!!
Rob
www.robs2000gt.com/mods.htm
Posted by TRY2PAZ (Member # 97) on
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I ran Autolite 764's gapped at .032
I had no problem with those. What fuel are you using? Which pump 342 or 317? What was your A/F above 5,000 rpms?Some people where having trouble switching to 91 octane
[ February 13, 2002: Message edited by: TRY2PAZ ]
Posted by robs2000gt (Member # 323) on
:
quote:
Originally posted by TRY2PAZ:
I ran Autolite 764's gapped at .032
I had no problem with those. What fuel are you using? Which pump 342 or 317? What was your A/F above 5,000 rpms?Some people where having trouble switching to 91 octane
[ February 13, 2002: Message edited by: TRY2PAZ ]
I got the tune on 91. I am running the 342, Byron said not to drill holes in the sump also. My A/F was 12 flat from 5000-5900 and then it went up to 12.5 at 6100. Now it seems that it is going lean sooner so i think the first thing i am going to change is the fuel filter since it has 42,000 miles on it and i am going to hope that it is that, also i am going to change the plugs. Should i gap that at .032 instead of .035?Thanks
Posted by TRY2PAZ (Member # 97) on
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Try autolite 764 at .032, if that doen't work, then try 100 octane and see if it makes a difference. Your A/F is fine. Mine went up to 12.6 at 6,200.
Posted by robs2000gt (Member # 323) on
:
quote:
Originally posted by TRY2PAZ:
Try autolite 764 at .032, if that doen't work, then try 100 octane and see if it makes a difference. Your A/F is fine. Mine went up to 12.6 at 6,200.
Thanks!!!! I will be changing the plugs and the fuel filter this weekend.
Posted by robs2000gt (Member # 323) on
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I just changed out the fuel filter. the fuel pressure seems to be more stable at idle and it is about 5-7psi higher at wot now. I checked one plug tonight and they look fine but have lost the gap and they are at .040. I will be changing the plugs tomorrow night and i will gap them at .032. The car seems to be a lot better just from changing the filter, so thats good news. Maybe i wont have to go with the new fuel system quite yet. It looks like i may be able to do the short block first.-Rob
Posted by TRY2PAZ (Member # 97) on
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Sounds good. How many miles on your car? I know Hoyston performance are selling complete short blocks. What is your fuel pressure at WOT?
Posted by robs2000gt (Member # 323) on
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quote:
Originally posted by TRY2PAZ:
Sounds good. How many miles on your car? I know Hoyston performance are selling complete short blocks. What is your fuel pressure at WOT?
i have a tad under 43,000. I was driving to the city for every day for about a year when i first bought the car. Since then i got on a vanpool so i only put about 5000-6000 miles a year on it now. Fuel pressure is at about 52psi at wot. Before i changed the filter it was only staying at about 45psi.
Posted by TRY2PAZ (Member # 97) on
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My old car saw 52-52 psi on my electris autometer gauge. Sounds like that was your big problem. Did u check into houston performance on the short blocks?
Posted by robs2000gt (Member # 323) on
:
quote:
Originally posted by TRY2PAZ:
My old car saw 52-52 psi on my electris autometer gauge. Sounds like that was your big problem. Did u check into houston performance on the short blocks?
yeah. They said i could get a fully forged bottom end, new block and a cobra crank for about $3000. Thats not too bad. I have the money to do it but i need to pay off my bills first. 