EGR removed and running bad
07-08-2014, 08:20 AM
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EGR removed and running bad
Ok, I think I have read every post on every forum regarding this topic. there is a lot of conflicting information out there. So I will describe my situation and hopefully someone can help.
While working on my '77 F150 with 351M, 2150 2 bbl. Carb with 1.21 Venturi and #57 jets, Non-cali emissions, I broke the Vacuum Volume Amplifier in the EGR circuit. I tried to repair it and it held for about 5 miles and then the truck started running horribly, basically knocking at any RPM and zero power.
I decreased the advance somewhat to try to stop the knocking and it did at the lower speeds. I have removed all the vacuum lines associated with the EGR since I cannot located a VVA and plugged the EGR port but left it on, plugged the Venturi Vacuum port on the carb, removed the 'T" to the spark port on carb and hooked it directly to the Dist, and plugged the manifold vacuum line going to the can. I have tried various settings in the Dist vac. advance from extreme sensitivity to the least, and nothing seems to help. Even though the sticker on valve cover asks for 14 deg BTDC I am running about 6 deg BTDC on timing right now and the only way to completely stop the knocking is to be about zero, but then there is stalling and hesitation and no power.
I cannot seem to get the air mixture correct on my carb. I can get the curb idle good at 650 rpm and when I put it in gear, it wants to die or acts like it will by making the entire truck shutter.
I read on Bubba's site that removal of the EGR will most likely require the changing of carb jets and advancing the timing. However, advanced timing is knocking and pinging like crazy. I also read that I may need to recurve the dist and that is fine as well. Bubba also suggested that a VDV might be necessary in the line between the dist and spark port, which I have also tried.
I really would like some help in correcting this age old thread.
1) how may steps up from #57 jets should I try, One site even said that I would need to go down. Can't really tell if its is rich or lean. I will look at the plugs tonight.
2) Recommendations on direction to re-curve, make it more or less sensitive.
3) EGR removal recommendations. Should I put a spacer in it, and has anyone bought one that they recommend.
4) Does anyone think it could have jumped timing? I checked it and foud it to be about 6 deg ATDC but I had been messing with the idle so i disregarded it.
This is a daily driver that I like to tow with and use it for what a truck is meant for so I am not looking for the best 0-60 time, but I don't want to destroy the engine with all that knocking. BTW, I run 100% unleaded gasoline with no ethanol. If that is not available, I run 93 octane.
Jim
While working on my '77 F150 with 351M, 2150 2 bbl. Carb with 1.21 Venturi and #57 jets, Non-cali emissions, I broke the Vacuum Volume Amplifier in the EGR circuit. I tried to repair it and it held for about 5 miles and then the truck started running horribly, basically knocking at any RPM and zero power.
I decreased the advance somewhat to try to stop the knocking and it did at the lower speeds. I have removed all the vacuum lines associated with the EGR since I cannot located a VVA and plugged the EGR port but left it on, plugged the Venturi Vacuum port on the carb, removed the 'T" to the spark port on carb and hooked it directly to the Dist, and plugged the manifold vacuum line going to the can. I have tried various settings in the Dist vac. advance from extreme sensitivity to the least, and nothing seems to help. Even though the sticker on valve cover asks for 14 deg BTDC I am running about 6 deg BTDC on timing right now and the only way to completely stop the knocking is to be about zero, but then there is stalling and hesitation and no power.
I cannot seem to get the air mixture correct on my carb. I can get the curb idle good at 650 rpm and when I put it in gear, it wants to die or acts like it will by making the entire truck shutter.
I read on Bubba's site that removal of the EGR will most likely require the changing of carb jets and advancing the timing. However, advanced timing is knocking and pinging like crazy. I also read that I may need to recurve the dist and that is fine as well. Bubba also suggested that a VDV might be necessary in the line between the dist and spark port, which I have also tried.
I really would like some help in correcting this age old thread.
1) how may steps up from #57 jets should I try, One site even said that I would need to go down. Can't really tell if its is rich or lean. I will look at the plugs tonight.
2) Recommendations on direction to re-curve, make it more or less sensitive.
3) EGR removal recommendations. Should I put a spacer in it, and has anyone bought one that they recommend.
4) Does anyone think it could have jumped timing? I checked it and foud it to be about 6 deg ATDC but I had been messing with the idle so i disregarded it.
This is a daily driver that I like to tow with and use it for what a truck is meant for so I am not looking for the best 0-60 time, but I don't want to destroy the engine with all that knocking. BTW, I run 100% unleaded gasoline with no ethanol. If that is not available, I run 93 octane.
Jim
