'88 5.0 starting/running problems April 12, 2005, 10:18:09 PM Well, it seems my thread in user rides has died off, so I guess I'll copy the relevant parts of that into a thread in here and try to figure out what's wrong with this thing.This is its general behavior:QuoteThe more times I try to start it, and get it to run for a few seconds at a time, the more it wants to stay running.. but by the time it starts getting easy to keep it going, the battery is dead and I have to give up. Last time before the battery ped out, it started hard, ran smooth, sputtered, recovered and ran smooth again, sputtered/recovered one more time, and ped out after about a minute total.This is the result of an experiment I tried:QuoteJust for the hell of it, I disconnected the IAC, (TPS is already disconnected/bad) stepped on the gas just a tiny bit, and tried to start it. Had no problem running it at over 1000 RPM for several minutes. Reconnected the IAC, pushed the pedal in again just a little bit, and tried to start it again.. did nothing but chug along barely running.This is a summary of things that might be relevant to the issue: (edited from the original thread where needed)Quote- TPS is bad. Read 5v when I tested it. When I ran it this time, I disconnected the TPS on Shawn's advice for this latest round of tests.- Gas is old. 2 gallons of it were in the car for well over a year. The other ~20 gallons are 92 octane (hoped the extra detergent might help a little) and were put in around the last week of October, along with two small bottles of gas treatment. The stabilizer was added somewhere around December or January, when I had to put some in the tank of our generator. However, many of you are of the opinion that this should be a non-issue.- We pulled one plug soon after I got the car here, and it was not fouled or damaged in any way.- Y-pipe precats are cleaned out, and are back on the car.- Smog system has been removed between the pump and that tube that connects to both heads. The tube is in place with the check valve on the end of it. I can plug it if need be. (also have a couple junk spark plugs I can stick in the holes if needed)- Looks to have new, but cheap, wires on it. Dist. cap and rotor are moderately worn. Fine-sanded the rotor contacts last night.- Has one known set of bad rings.. I believe he said some mechanics told him #2's rings were shot. It blew a LOT of oil up into the throttle body via that hose connected to the oil filler tube, when I first got it and tried to run it. This time around, I'm not seeing any oil being blown out.- Has new vacuum lines connected to most of the intake manifold, based on the picture floating around here from when I asked what goes where. I've done a reasonable amount of tracing of the lines, and saw no obvious problems with my reassembly of the system.- New fuel filter.- New PCV valve.- Already reset the switch in the trunk.The main question is, *should* this all clear up when I replace the TPS, or might I be looking at more serious problems? Quote Selected
Re: '88 5.0 starting/running problems Reply #1 – April 13, 2005, 05:08:42 AM Its gonna be impossible for the EEC to learn how to "idle" the engine with a bad TPS. Were the voltage readings taken from the green and black wires??? Quote Selected
Re: '88 5.0 starting/running problems Reply #2 – April 13, 2005, 09:48:53 AM To the best of my knowledge, yes. It's been a few months since I took the reading.I should be picking up a new TPS today. Quote Selected
Re: '88 5.0 starting/running problems Reply #3 – April 13, 2005, 12:38:27 PM Got the TPS, installed it.. car mostly behaves the same, except I can keep it running with my foot on the gas. I'll have to adjust the TPS now (I just slapped it on there to try it) and check codes again. Quote Selected
Re: '88 5.0 starting/running problems Reply #4 – April 13, 2005, 01:46:20 PM Alright.. had another dead battery issue, which is now solved.TPS is adjusted to .95 or .956 or something like that.Started the car.. it will not keep idling on its own.. it'll out after maybe 10 seconds.If I disconnect the IAC and try to run it, it will just out after 2-5 seconds every time.If I hold my foot on the gas and tweak it constantly, I can get the car to maintain about 1400 RPM.. but it'll maintain that for 10-20 seconds, start to chug, then flare up and level off again. If I let off the gas, it'll drop to 600-800 RPM for 10 seconds or so, then die quietly. I had it running long enough to get it to three bars on the temperature gauge, (full digital) but I decided to let it charge up a bit more before I messed with it again. Quote Selected
Re: '88 5.0 starting/running problems Reply #5 – April 13, 2005, 01:53:04 PM Disconnect your EGR and see what happens Quote Selected
Re: '88 5.0 starting/running problems Reply #6 – April 13, 2005, 01:54:37 PM Pull the EGR off the spacer or the lines off the EGR valve? Quote Selected
Re: '88 5.0 starting/running problems Reply #7 – April 13, 2005, 01:55:14 PM pull the lines.... Quote Selected
Re: '88 5.0 starting/running problems Reply #8 – April 13, 2005, 02:06:14 PM Pulled the electrical connection to the EGR valve, it runs mostly the same. It'll hold idle for a little while longer if I let my foot off of it, but it still dies.On a brighter note, I was able to run it long enough to move it out of its parking spot for the first time since November. Quote Selected
Re: '88 5.0 starting/running problems Reply #9 – April 13, 2005, 02:56:28 PM OK.. with EGR still disconnected, I got it to run.. even drove it around the yard briefly. Got it back near its spot, and held the revs up for a little while. (2-3k) When I let off, it idled. The idle is a little rough at times.. like one cylinder not firing on occasion.. but it'll stay idling once it's warm.If I try to rev it, it'll bog down but then rev up to 2-4k without any other problems. Quote Selected
Re: '88 5.0 starting/running problems Reply #10 – April 13, 2005, 04:10:51 PM I'd say your EGR seems to have something to do with it, but there is something else still wrong besides that.QuoteHas new vacuum lines connected to most of the intake manifold, based on the picture floating around here from when I asked what goes where. I've done a reasonable amount of tracing of the lines, and saw no obvious problems with my reassembly of the system.Do you know which lines are still off? Maybe one of those missing ones? Quote Selected
Re: '88 5.0 starting/running problems Reply #11 – April 13, 2005, 04:15:26 PM Well, I made one modification to be able to keep EGR vacuum and lose the vac lines to the smog pump's valves.. there was one line that splits into two, the top line goes to EGR and the bottom goes to the smog pump . I cut the splitter in such a way that I could run a line from the original single line right to the EGR line, but if I ever needed to connect things back up again, I could do it with just two little pieces of my blue vacuum line.I never did account for the line that ran into the body at the very back corner of the passenger side of the engine bay, but it was connected to one of the smog pump solenoids.If I patch that line back to the way it was, I'd still have the smog pump vacuum lines open.. there's nothing left to attach them to. Quote Selected
Re: '88 5.0 starting/running problems Reply #12 – April 13, 2005, 08:47:54 PM Aight, it runs.. and it'll idle steady around 800 RPM now, but only if I disconnect the IAC. If I don't, she'll crank and crank and crank and TRY to start but will never quite catch and run.I sorta cheated on adjusting idle and the TPS. Since I knew before my last TPS adjustment that idle was a little on the high side, (it was regularly fluctuating between what I am guessing is the 800 RPM bar and the 1000 RPM bar on the digital tach) I got the TPS voltage as low as I could possibly get it (like 1.020v) and then made up the difference by turning the idle screw back down until it hit .98v exactly. (maybe less than one full turn to the left)I'm not going to mess with it any more tonight. That battery is taking a beating. Quote Selected
Re: '88 5.0 starting/running problems Reply #13 – April 13, 2005, 11:07:19 PM cool, guess you found your issue. As far as your battery is it still goin south on you after letting it sit for a while? Quote Selected
Re: '88 5.0 starting/running problems Reply #14 – April 13, 2005, 11:22:45 PM So the issue is now the IAC? I can only get it to run close to normal when the IAC is disconnected.I also can't rev it freely.. if I push on the pedal quickly, it bogs a few times.. if I want to rev it, I have to do it carefully, working the pedal quite a bit. But it will eventually rev, even up to 5k+.The battery doesn't go south on me from sitting, it goes south on me from cranking it over so much. It often takes 5-10 seconds to start the car, longer if I even turn the parking lights on. (which I need to do to illuminate the dash properly.. separate issue) I have it on 2A charge overnight, and I'll juice it tomorrow with 6A while I'm out there.This stuff may or may not be related, but I know I need to get a new negative terminal put on that wire. The current one is mangled. I also need to get another coil on it. The coil on it now is the one from the '86, because I put the "new" coil I bought on the '86 when I did a tune-up. It was originally meant for the '88 but I knew the '88 would be sitting awhile. Anyway, the coil's contact for the coil wire is somewhat eroded from its time in the '86. Quote Selected
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