Trevor571548534737 Posted July 19, 2010 Share Posted July 19, 2010 Last event a month ago we were having some bad misfire issues, and replaced the ign coil on saturday night. Sunday morning the car was running well and went very quick. put the car on the trailer and parked it. I didn't do any motor related work in between then and this last weekend at Autobahn. First session saturday morning the car immediately had a misfire at wot above 4k rpm. I did about 2 laps and came in. We replaced a questionable plug wire, double checked any grounds, or loose connections went back out and it was much the same. That was it for saturday, since I had to leave early. Sunday morning we replaced the tfi ignition module, and went out to find the car way down on power but not specifically misfiring. I came in and we checked, and set timing to 12 degrees. Headed out to grid for the next session, and the car popped the 150 amp fuse that is on the main battery cable. When I would crank it I was starting to notice that there was kind of a "flat spot" when I would try to start it. It would crank but about once per rev it would kind of bog down, and I believe that was what popped the fuse. We got the car back, and coincedentally were going to replace that old fuse holder anyway so we already had a nicer new one waiting. We replaced the fuse holder with a 200 amp and fired it up. I noticed the same flat spot with the starter but the car fired. Went out again only to have the same problems. That was the last session before I said screw it. I parked the car after about 3 laps and It was extremely hot, and was dumping water into the expansion tank. I could not get it to fire to get it on the trailer. The battery is showing 12.0 volts as it sits, but if you hit the starter it just clicks once. I looked at the traqmate data for a reference, and the hp/distance value was always right at 250hp at blackhawk and at ACC it was just under 200hp. Where should I start? Quote Link to comment Share on other sites More sharing options...
mitchntx1548534714 Posted July 19, 2010 Share Posted July 19, 2010 Where should I start? The problem lies in your avatar. Quote Link to comment Share on other sites More sharing options...
KiMifan Posted July 20, 2010 Share Posted July 20, 2010 Where should I start? The misfire sounds like a voltage-related ignition problem. 12 volts won't cut it with an EEC-IV. It needs to have full alternator output (~13.5V). Coupled with blowing the main fuse, I'd take a look at the alternator. Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 20, 2010 Author Share Posted July 20, 2010 That is 12v with the car off. When I hit the starter button, the starter tries to turn but can't. I believe that is why the fuses have been blowing. either the starter teeth are not meshing with the flywheel, or something is siezed in the motor i think. Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 20, 2010 Author Share Posted July 20, 2010 I just pulled the starter out and it spins like a top. So I guess the flywheel is stuck. Is it time to open the motor? Quote Link to comment Share on other sites More sharing options...
mitchntx1548534714 Posted July 20, 2010 Share Posted July 20, 2010 Where should I start? The problem lies in your avatar. C'mon ... that was funny. You guys need to lower the rev limiter a tad ... Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 20, 2010 Author Share Posted July 20, 2010 The crank spins via wrench freely, and a visual inspection of the FW looks good. Quote Link to comment Share on other sites More sharing options...
Den341548534727 Posted July 20, 2010 Share Posted July 20, 2010 If you disconnect the spark ignition IE distributor does the engine turn over freely with the battery and does it still have a "flat spot"? Just wondering if the timing is way way advanced and the engine is firing against itself while you are cranking it over. Maybe a distributor / timing issue. Quote Link to comment Share on other sites More sharing options...
nape1548534725 Posted July 20, 2010 Share Posted July 20, 2010 I had a starter last year that would spin fine unbolted from the block but when it was bolted up, it didn't have enough guts to spin the motor over. Take the starter to Autozone and have it checked. If you don't want to do that, at least inspect the solenoid and make sure it isn't cracked/draining to ground somehow. Put the battery on a trickle charger to get it up to full strength then flip it over to start and see if it'll spin it fast enough to light the motor off. Check the battery again to see if you have 14+V. You should have ~12.5V on a battery, so I'm guessing it's a little weak and maybe the alt isn't charging. Even if that fixes it, double check the timing to make sure you didn't read it backwards and dial more advance in. I did that by mistake last year and burned two pistons. Quote Link to comment Share on other sites More sharing options...
rocky Posted July 20, 2010 Share Posted July 20, 2010 Did you check voltage when you cranked it? If the voltage drops below 10.5 volts something screwy is going on.More than likely a bad battery possibly the starter. If you can do a starter draw test that will let you know what to look at. Quote Link to comment Share on other sites More sharing options...
FBody383 Posted July 20, 2010 Share Posted July 20, 2010 More than likely a bad battery possibly the starter. If you can do a starter draw test that will let you know what to look at. Also check the cables and make sure the terminal crimps are good. I had what I thought was a starter/hot start condition that was a bad terminal crimp on a cable I made. Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 20, 2010 Author Share Posted July 20, 2010 Ok, took everything to AZ and the battery and ALT are fine. The bendix on the starter was jacked and apparently binding against the flywheel. I replaced the starter and now the car starts. Now I need to diagnose this misfire...... Quote Link to comment Share on other sites More sharing options...
nape1548534725 Posted July 20, 2010 Share Posted July 20, 2010 I would check the MAF if you've replaced the TFI and coil already and it's still missing. I've got a MAF for a '96 T-bird in the rafters if it happens to be the same one and you need a part to swap for a test. You checked fuel pressure at Blackhawk and it was solid, right? Quote Link to comment Share on other sites More sharing options...
liebbe1548534713 Posted July 20, 2010 Share Posted July 20, 2010 I've seen a Mustang do similar tricks as yours with low voltage. It will run good at low rpm, but fall over at high. That one turned out to be a weak alternator and thus low battery voltage (like 12 V) if I remember right. I know you had your alternator checked, but at what temperature did you check it? I bet Autozone was cooler than under your hood. Good luck - I hate electrical gremlins. Mitch - I laughed at your avatar joke. Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 20, 2010 Author Share Posted July 20, 2010 I haven't checked fuel pressure yet. The maf is brand new, but I have another to swap with just to make sure. Quote Link to comment Share on other sites More sharing options...
TurboShortBus Posted July 20, 2010 Share Posted July 20, 2010 Don't forget to throw another distributor at the engine to see if the stator could be the problem. You are better off testing this with an old OEM Ford distributor than a new/reman/MSD Pro Fancy distributor with a non-Ford stator. Borrow one from a buddy, if possible. The next time your starter won't crank the engine over, roll that mofo out in the street and push start it to see what happens. Remember...it is almost never as complicated as you first think it is. Mark Quote Link to comment Share on other sites More sharing options...
TurboShortBus Posted July 20, 2010 Share Posted July 20, 2010 The problem lies in your avatar. "At least they circled the problem." Mark Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 21, 2010 Author Share Posted July 21, 2010 Did a compression test tonight. Warmed up the car and heres what I got. 145 125 140 130 100 130 140 120 front of car I squirted some oil in the low cyl and got maybe up to 105. So bad valve maybe? Is this bad enough to worry about or should I keep looking outside the motor? Quote Link to comment Share on other sites More sharing options...
TurboShortBus Posted July 21, 2010 Share Posted July 21, 2010 I drove my 1994 Mustang around for about 5 years with 1 cylinder significantly lower than the other 7, and it didn't have any kind of a misfire. It even made its quickest dragstrip passes with 2 cylinders that were under 100 psi (broken ring lands), and it wasn't missing. Look elsewhere. How is that distributor swap coming? Mark Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 21, 2010 Author Share Posted July 21, 2010 I need to find a distributor. I went on the napa website, and they list a steel gear one, and an iron cast gear. That scared me, since I have no idea which one I need. Craigslist didn't have any promising leads, and I can't get to the boneyard until this weekend. Quote Link to comment Share on other sites More sharing options...
TurboShortBus Posted July 21, 2010 Share Posted July 21, 2010 You need the distributor gear that is compatible with the camshaft material you are using. Go to page 3: http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-12390-A.pdf A Napa distributor will likely have a "white box" stator, which may or may not be any better than a bad one. Use Ford stators only. Mark Quote Link to comment Share on other sites More sharing options...
Trevor571548534737 Posted July 22, 2010 Author Share Posted July 22, 2010 I bought a napa distributor, and headed out to the drag strip to t&t. I did a baseline, and ran a 14.9 @92. I swapped out the dist, and reset timing, and nothing really changed 14.7 @ 93. I swapped out the IAC and was headed back out, and the battery couldn't get the job done. I pushed it back into the pit, jumped it, and bailed. The only parts I have not changed out are tps, iat, egr, fuel pump, and injectors, battery, and alternator. I may just replace it all. unless ya'll have some input. Quote Link to comment Share on other sites More sharing options...
nape1548534725 Posted July 22, 2010 Share Posted July 22, 2010 I wouldn't go replacing parts just yet. Have you checked your fuel pressure and running voltage yet? Sounds like you still have a charging problem but we need to know what the voltage on the terminals is with the car running. Quote Link to comment Share on other sites More sharing options...
rocky Posted July 22, 2010 Share Posted July 22, 2010 Trevor57 do not start playing mechanic baseball (throwing parts at it) it gets expensive quick. You definetly need to figure out your starting/charging problem first. It can cause a miss problem. Keep posting what you have done and someone here will help you get it figured out. Quote Link to comment Share on other sites More sharing options...
TurboShortBus Posted July 22, 2010 Share Posted July 22, 2010 Shotgunning parts at the car is fine as long as you save your receipts and return the parts that don't help. Mark Quote Link to comment Share on other sites More sharing options...
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