Already have done both. Fuel gauge "T" in right at the TBI and gauge is on the dash so I can watch it. Fuel pressure is solid even above 2000rpm. Did a fuel volume check and it passed. The TBI system only requires 9-12 psi and I have a steady 11. I notice the tach drops for a split second when the flat spot happens, but the engine rpm is not dropping in relation to the tach. That makes me think the ignition is cutting off for just a second. With no change in throttle position it perks up and pulls to 2500 and I shift. Then same response thru the next gear. I did replace the TPS and checked voltage while thru the entire range. Next trying to get my timing light where I can watch when driving to see if I am loosing spark. Damn thing looks like a rolling laboratory with all the hoses and wires hanging out the windows. I do not have a OBD1 scanner to watch the fuel trims but I did confirm the O2 sensor is working. Also ran without O2 sensor plugged in which should have put the fuel trim in default, made no difference.
2F Fuel injection installation???????? (1 Viewer)
- Thread starter boerboel313
- Start date
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Check to make sure you don’t have oil coming up the distributor shaft and into the electronic parts under the rotor. I had this issue and it would cause the timing to be all over the place.
Oh I have not checked for that. I will do that and let you know what I find.
Pulled the cap off this weekend and this is what I found. No idea what this is. It is a very fine powder with maybe a touch oil. Just enough oil that it clings to everything and can not be blown off. I do not see any form of mechanical advance. The distributor was part of the fuel injection kit and could be some cheap China part. Also the rotor can rotate about 1/4 inch without rotating the drive shaft, not good. To set base timing there is a wire that gets disconnected and takes the computer controlled timing out of the system. I disconnected the wire and went for a drive and it ran much better. Just low on power but I think that is due to no advance. So ignition seems to be the problem but need to figure out what this powder is and where is coming from. Looks like it is causing some arching on the top of the rotor. Might be time for the DUI dizzy if that can used with the GM TBI fuel injection.
UPDATE- The powder is rust. My cap is vented but does not a port for the vacuum hose.
UPDATE- The powder is rust. My cap is vented but does not a port for the vacuum hose.
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Make sure at wot your tps reads and 100% throttle. The tbi gm map sensor is a common failure point. The only spark issues that are common are bad connections of the electronic wires. If the magnetic pickup loosens in the distributor it can cause issues with spark as well as play in the distributor shaft bearing.
So I cleaned out all the mess (rust) re-set the timing and it runs as good as ever. The Toyota cap has much larger vents then the aftermarket cap so I put the Toyota cap on. I am also going to run a vacuum hose from the vent to the air cleaner like the factory carb set up did. Maybe that will stop the condensation. I think all that fine rust powder was flying around under the cap and causing the spark to jump all over the place.
I did a bunch of research on this while diagnosing a vacuum leak. What I came across was advice to not run a vent straight between the distributor and air cleaner. What can happen is that gas fumes can vent from the carb through the air cleaner and down into the dizzy when the engine's hot and potentially cause ignition in the distributor during a hot start. That's why the stock vent setup has a VCV inline. FYI.
Of course, if you already intended to add the VCV then ignore this
