5.0 runs like crap, then run's ok

[GRM-REPR]

I cant seem to get anyone to help me on this issue before I just start throwing parts at it, I cant even get people to give good suggestions on the Corral and that's rare.

It's an 87' 5.0, I did the MAF conversion, so no speed density. My timing is at 14* and 1.5* on the dial of the MSD6BTM. Fuel PSI is at 45 line out. It's supercharged with goodies. A9L ecm, I DONT have a custom chip. Granatelli 75mm MAF 70mm BBK t.b.

When I say practically everything is pretty new on the car and engine, I mean it. All those sensor's people say to check are new, and I checked those before ever posting. I deleted the smog system completely from the car and the O2's have under 4k on them.

NOW THE PROBLEM>>>>>>>>>>>>>>> For a while now the engine has been acting like it has a noticeable miss when cold, seems to go away when it gets warm. At anytime idiling at a light, it will kill for no reason. It will also at a stop just idle up to around 2,500rpm's whenever it feels like it, then when I try to knock the idle down, it wont. A couple of times if I shut the engine off the idle would be back to normal (950rpms). Now, when it kills and I restart to drive, it will start fine but then the car has NO power and cough's and surges. When I stab the pedal, I watch out the back and the pipes shoot out massive Black smoke, I thought that means a rich condition?, which is impossible seeing as how I have my fuel psi set safely.

I would like to believe I've narrowed it down to 2 possible problems. The injectors are used 24's I bought on a budget 2 yr's ago, supposedly with 50k on them. Also, the BBK throttle body, seems every time I try to adjust my idle below 900 it will make the engine rpm's go WAY low and then to 1,500 rpm's and keep doing it unless I raise the idle back up to over 900.

If I left out any components I have then let me know. I'm out of ideas and want to drive my stupid car. Thanks in advance, JON....

[MurphysLaw88GT]

ignition module on the base of the distributor? i had one take a **** on me once

[Irish]

or thottle positioning sensor

[GRM-REPR]

The dizzy is brand new, Accel billitech.

Irish, tps has less than 4k on it.

I got some replies on the Corral and they were pretty weak. I ordered injectors today and I'm going to start there. I unplugged the IAC and the idle dropped just a bit, I thought they were supposed to kill when unplugged??

Keep the replies and suggestions coming!!!

[Greg@GLD]

You are describing problems that are typical of a mass air meter problem. Does not matter what you have your fuel pressure at, if the mass air meter is messed up or incorrectly calibrated, the car will run like crap, period. It's hardly "impossible" for it to run rich. Fuel pressure reading on a guage does not in any way tell you how rich or lean you are. It's much more complicated than that. A wideband 02 sensor is going to tell you where you are at. How do the plugs look? How are the tailpies?

FYI, removing smog devices, especialy the EGR can hurt more than help. I make 500 horses to the rear wheels with the EGR fully functional.

Might want to try re-clocking your mass air meter and see if that changes anything. Also might want to make SURE that it's been properly calibrated for the injectors. Also might want to double-check all your tuning from the meter to the TB and make sure there are no leaks.

[Greg@GLD]

tailPIPES... oops.

[Reverend Cooper]

does the car show any codes. also adjusting the idle at the throttle body will screw up everything with the tps. this can cause the problems your haveing. one other item i would look at is a fuel press. regulator if it is leaking gas into the vacuum line it will run rich and like crap also..also new parts can fail remember that

[Prince Valiant]

Have you checked the voltage running to the throttle position sensor yet? Have you tried reseting the idle?

[Lash]

First thing I would do is check for codes.

[GRM-REPR]

Yes, I need to check codes, which have usually been bunk for me seeing as how I've removed all smog components.

Greg, the MAF is new from Granatelli, this one was custom built by a tech I talked with because the harness' they sent me originally were crap. Yes, the MAF is cal'd for 24*'s, I have not tried to clock the MAF, (thought you do that only on C&L's). This problem that I have now, (killing, high erratic idle, and lack of power) didnt happen until roughly over a month ago, I had the new MAF in back in late April.


Sonic, I found no gas in the line at all for the fuel psi reg. I did happen to notice tho today when I looked under the hood that the fuel psi was at 35 lbs, which is odd, seeing as how I havent started or cycled the key since yesterday??? Didnt know that you had to re-adj the TPS after messing with idle.

This problem just seems so damn phantom to me, I used to be a Ford tech for years and I'm stumped and pissed off.

Also Greg, the thick black smoke I get out the TAILPIPES (LOL) were doing this way before I even had the new MAF. Like I said before, the injectors are about the only used parts left on the engine.

Plugs seem fine also. I did have a lingering problem I did solve last week, I got electrocuted by my MSD coil, dont know why. I put my stock bracket and other MSD coil on and no zap's at all. The car was randomly killing for no reason, I even shut my hood a couple of times and the engine would kill, so I believe this is a dual problem??

Thanks for all the good suggestions so far!!!

[Greg@GLD]

Do you have an FMU on this car by chance? And it sounds like you have the FP gauge underhood, which means you can't see it when under boost? I wonder if your FMU (assuming you have one) is hanging up. That would cause the extreme over-rich condition. If you can't monitor fuel pressure while under load, it's possible this is what ails you. I would assume that you do have an FMU if you are using a BTM also.

Just for the sake of diagnosis, have you done a leakdown test n this engine?

You might want to get in touch with Paul Graham, he's a master Ford tech and he knows his stuff. He lives somewhat close to Waukesha. PM me if you want contact info.

[GRM-REPR]

Yes, I am runnig the FMU that came with the kit. Your also right about the fuel gauge being under the hood. Then I would assume that something has been wrong from the start because it's been rich black smoke since the install of all the mod's (s/c, intakes,cam, etc). I did a clutch a couple of weeks ago, when the Xpipe was off, it was coated black on both sides, when the car is idiling in the gargage for even 20 sec's it will stink up the place HORRIBLY, like too much unburned gas going into the engine.

Thats sort of why I figured injectors, one or more are worn out, or one that has blockage and is leaking excess fuel into the cylinder.? How would the FMU hang up?

As far as a leak down test goes, when I popped a h.g 2 yrs ago, I did one, all cylinders had good comp. I'm getting no coolant lose, no oil consumption beyond normal conditions.

I've got everyone stumped pretty good, the members on the Corral are still stumped and not even replying anymore.

What code tester would be good to pick up because I dont own one??

Thanks again for the help.

[GRM-REPR]

I just went out there this morning to re-clock the MAF, (did) and I happen to look at the fuel psi gauge, it went UP to 40 psi?!, which is strange because when I pulled it in the garage it was at 30 even. Yesterday I went under the hood and the car hadn't been started or the pump cycled and it was at 30 psi?!

I played around with the fuel psi, when I'd go to cap off the vac line to adj, the idle seemed more smooth. The idle then just went up for no reason, I was tapping on the TPS and sometimes it seemed to make the idle change. When I'd put the vac line back on, then idle would just stay higher more often and not change if I tapped the TPS. I set the psi to 45 line capped but when I put the vac back on, it is over 40 at idle. I'm confused, LOL>....

The gauge is good and is accurate. Why would the fuel psi go up?, it used to always leak down after about 30 mins. It's a Walbro 190lph pump with probably less than 2500k on it. Mallory fpr and stock fuel rails. Would it not be smart to bypass the FMU right now? I've seen many people go without them but they have bigger injectors, just seeing what my options are.

[Greg@GLD]

Would it not be smart to bypass the FMU right now? I've seen many people go without them but they have bigger injectors, just seeing what my options are.

NO. Do not do that! If you make boost with no FMU and 24lb injectors you are gonna melt something. The whole idea behind ditching the FMU is predicated on having larger injectors PLUS forcing them to be open in a longer pulse-width via external tuning from either a chip or a PMS or other external tuning device.
You perhaps know this already, but in case you don't- The way that FMU operates, is that when the FMU senses boost, it blocks the return line back to the tank, and this causes the fuel pressure to go much higher than "stock" which in turn causes the injectors to spray more fuel during the injector pulse. The injectors "act bigger". While it's not ideal, it's safe (rich)
If you disable the FMU, but do nothing to modify the injector pulse-width or run a larger injector, when you make boost, you will pop a head gasket at best, and probably melt a ring land or put a hole in a piston or ruin the engine at worst. DO NOT RUN IT WITH 24 Lb injectors and no FMU!!!

If the FMU is hanging up, it will cause a very rich condition.

[Reverend Cooper]

how about the fact that you have not reset the idle properly first. go online and there is specific instructions. something like this.warm up car disconnect battery, unhook tps.start up set base idle with screw,then shut off and check tps voltage set to @.96 v while not running just key on. shut off key plug in tps and restart. now no flaming i am going by memory. get that right first before you go any further.the car should run noticeably diff with the vac. line disconnected at the press. reg. happy hunting and dont get discouraged

[GRM-REPR]

Thanks Greg for the schooling on FMU's.

Sonic, I'm going to buy a new TPS and adj accordingly.

Injectors and such should be here tommorow and with the new TPS set properlly, I'll update the thread, something tells me I'm still going to have this headache when I'm done.

Thanks again guy's..

[Irish]

tps, me, two days ago.

[GRM-REPR]

Yes, Irish i c LOL...

I just dont think it's the TPS but it can't hurt to replace it. Seem's when the vac line to the fuel reg is reconnected the idle (when it's erratic) the TPS wont change the idle if I tap it, or so it seems. When the line is off, it seems to react, ???

[Irish]

change it to a blow threw carb application

[FourEyedFord]

how about the fact that you have not reset the idle properly first. go online and there is specific instructions. something like this.warm up car disconnect battery, unhook tps.start up set base idle with screw,then shut off and check tps voltage set to @.96 v while not running just key on. shut off key plug in tps and restart. now no flaming i am going by memory. get that right first before you go any further.the car should run noticeably diff with the vac. line disconnected at the press. reg. happy hunting and dont get discouraged

Daaaaaaaaamn! That is a lot of work for just setting idle speed.