Engine Problem
Need a little help.
Went for a drive this evening to test out some sound deadening.
Motor was warm, running fine.
Went to pull out from a stop to come home. As I got on the roadway, I saw headlights in the rearview and gave it some throttle to get up to a little quicker.
It was pulling first gear nice at about 75 % throttle and as it got to 4500 or so, I heard a loud pop and let off the throttle. I coasted to the shoulder and checked the gauges. Oil pressure was fine, temp was fine, MAP at idle was fine, AFR was fine. The only thing that seemed off at idle was a little more noise from the Rhoads lifters (at least that's what it sounded like).
I tried to give it some throttle and it would buck and pop out the exhaust. I was able to limp it home and got it on the lift. Nothing out of place underneath. I hooked up the timing light and vacuum gauge and tried to start it. Fired right up and settled in to a nice idle. Vacuum gauge and FITECH control module read the same, 15. Timing was spot on at idle at 18 on both the timing light and the control module.
Scrolling though all of the FITECH readings on the dashboard, everything looked great.
As soon as I try to give it any throttle, the MAP jumps to 75-85 and it pops out the exhaust. When it pops, the AFR's are showing steady at 14.70.
I did check the FITECH for faults and it should Wideband. I cleared the fault code and started it back up. I let it idle for a bit and checked the faults again. The code did not show up in the short idle session.
Any thoughts? With the MAP readings going so high off idle, I don't know where to start. I'd lean towards a bad MAP sensor?
Thanks.
Can you send a Datalog? Must use a link from Dropbox or Cloud.
How do I data log? Which feeds would you recommend tracking?
Car started to day and idled fine. I cannot open the throttle at all without it popping. When I open the throttle, it feels and sounds like its going to die and then pops. I can't bring the idle up even 50-100 rpms with the throttle. The system can adjust idle no problem. When I start it, it will go to 1000 rpm and then settle down to 750 as it always had.
I'm wondering if the pop at the top of 1st gear was a lean backfire through the throttle body. Could that have damaged something in the throttle body?
AFR's read consistent between the handheld and the dash gauge. Vacuum readings between a gauge and the handheld are consistent and react the same when the bucking and popping occur.
TPS reads 0 at idle and 99% at full throttle (when checked with the motor off) and seem linear. Idle steps are 6 at idle.
Problem seems to be at tip in or transition from idle to off idle. Plug wires were checked and tight and not shifted to where they crossed.
Pull plugs and read.
I do not have a tutorial on datalog, but there is plenty of information on how to do it.
I did a data log. I'll try to get a way to share it.
It immediately showed fault 105 at start up and then the fault went away after the first 10 lines of data and never returned.
When I open the throttle it transitions from a run state of idle, to dash, to tail, back to idle as it let off the throttle.
The only thing that I have seen so far as it pretty consistently drops 200 rpms on throttle opening and then jumps 400-500 rpms.
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See if this works. It is supposed to let you read it on my One Drive.
If those links don't work, I can email it to you.
Log looks good. I see a small lean tip in. Do you have a fuel pressure gauge. Wonder if you are losing flow due to a filter or pump.
I have the gauge on the FCC. It is showing steady state 58 at idle.
Car is acting as if its rich as its popping out the exhaust when I try to open the throttle.
I couldn't see anything obvious on the data log either.
Do you know the definitions of the run states? I'm assuming dash and tail are correct?