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So I swapped 5.0 with A9L computer and harness into my 89 F150. The engine is a 302 w/ custom valvetrain, Trickflow TW heads, Cobra intake, 70 mm TB, 70mm MAM, and supporting cast. I cannot get the thing to idle without leaning it out enough that the headers start glowing, will barely idle in traffic, just a complete driveability nightmare. What is the order for setting things like the fuel pressure and timing, idle control and such? I wanna pull this thing out and find a carbed car to put this in, but I gotta exhaust all possiblities of it working right before I do something that drastic.
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Bakersfield, CA. -
Re: EFI troubles with 5.0/ A9L
The cam you have, is it the HO 1-3-7-2 firing order? Just checking the basics first ...
cheers
Ed N.Ed Nicholson - Caledon Ontario - a bit NW of Toronto
07 Mustang GT with some stuff
88 T-Bird Turbo Coupe 5-speed -
Re: EFI troubles with 5.0/ A9L
Which tuning package are you using to tune the A9L box?
Is the MAF the same one that was with the computer in the Mustang?
Set the fuel pressure regulator to 39 psi without the engine running but the pump on. If the pump only runs when the engine does, then set it to 25 psi when the motor is pulling about 15 inches of vacuum.
Make sure the timing is set to 10* BTDC with the little do-hickie pulled off the distributor, also as close to idle as you can get.
If you cannot get it to idle below 1000, check for vacuum leaks, like the IAC or around the throttle body. Extra air will make it impossible to get right.
JohnComment
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Re: EFI troubles with 5.0/ A9L
when the headers glow and you're leaning it out, that is a dead giveaway that your timing is WAY retarded. Like, a whole tooth on the distributor... triple check your ignition timing and make sure you have all wires in proper order, going to the right plugs etc.Originally posted by cantvalve16www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!Comment
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Re: EFI troubles with 5.0/ A9L
Thanks for all the responses guys. I will check the timing and plug wires like you guys said.
Fast Ed: The cam is a custom cam by Camshaft Innovations (Jay Allen). It was made for this engine with this supporting cast in this truck and is the HO firing order.
Prorauder: With the fuel pressure set at 40 psi at idle and vacuum connected, the driver side header glows red hot when revved to about 2500 in park for a few minutes. Set like this the idle will maintain at about 750 rpms.
The computer is an A9L from a 91 Mustang with a stock tune. The MAF is from a different car. Pro-M calibrated for the 24 lb. injectors the truck has.
I have not tuned the computer at all. I have been trying to get the thing run half decent so that I can go get it dyno tuned.
Dieselgeek and Beagle: I will double check my timing and ignition equipment. Last I checked, I had it set to about 13 degrees advanced. I have heard that with aluminum heads, the timing can be advanced to about 17 or so for maximum efficiency.
Thanks guys. Any other ideas before I head out to the garage?Bakersfield, CA.Comment
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Re: EFI troubles with 5.0/ A9L
Ok... soo....I must have left the dist. hold down loose the last time I played with the timing because it was wayyyyyyy retarded. NO advance with spout in. The timing was on the TDC mark of the timing tape. So, I advanced it to 14 degrees spout out for a functional timing setting of about 21 degrees. Then I began to set the fuel pressure, but the upper intake got to hot to touch as I had it running the whole time. I have some more to do with it once it cools down. Went out and drove it and driveability was better than ever. Now it doesn't stumble at low speeds until it hits third. Then it sputters and coughs until I get out of the neighborhood. Has a weird shudder to it in 3rd through the residentials.
Gotta play with the fuel pressure some more and do a base idle reset as well as clear the codes and check them again.
I cannot believe I made such an elementary mistake when I am sitting here swapping harnesses and computers. Here I am making dumb (yet very frustrating) mistakes. Thanks for being there when I need you.
BrianBakersfield, CA.Comment
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Re: EFI troubles with 5.0/ A9L
With the car at idle and the vacuum connected, the rail pressure should read about 25psi depending on the inches of vacuum the engine is pulling. IE: If it has around 15" of vacuum, the rail pressure will read about 25psi. When it reaches 0" of vacuum, it will read about 39 psi. If you pull the vacuum line off the regulator, you should see 39 psi. If not, adjust to 39 and then put the vacuum line back on.Originally posted by cantvalve16
Again, this assumes you are running a regulator that is adjustable. I would think the factory fuel rail sensor would do exactly this.
But as others have stated, it does sound like a timing issue that will need to be looked at first.
JohnComment
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Re: EFI troubles with 5.0/ A9L
With:
no vacuum to the regulator,
the fuel pressure set at 39 psi,
timing at 14 degrees advanced spout out,
No preload on the lifters, just no lash,
idle at 750,
I got 15 inches of vacuum and the idle was relatively smooth.
Once I preloaded the lifters, the vacuum went down to 11 inches and the idle a more nervous.
My cam guy spec-ed the cam to put the engine at 16.5 inches of vacuum and idle like a kitty. I resolved the red hot header issue. What else should I look at?Bakersfield, CA.Comment
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Re: EFI troubles with 5.0/ A9L
What are the cam spec's?
It may like a tad more initial.Comment
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Re: EFI troubles with 5.0/ A9L
be careful with that, because if he rotates the distributor for more advance on the EFI setup, then he is also advancing his cruise and WOT ignition timing as well.Originally posted by min301
My vote is to check for vac leaks, or look at an oxygen sensor to see if his mixture goes south when it loses vacuum. And double check that the timing isn't falling way off...www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!Comment
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Re: EFI troubles with 5.0/ A9L
Alot of them seem to like more initial, but those are good things to lookOriginally posted by dieselgeek
at before making any changes at this point.Comment
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Re: EFI troubles with 5.0/ A9L
How do I test the O2 sensors? I know I probably need a volt or ohm meter, but what is the procedure?Bakersfield, CA.Comment
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Re: EFI troubles with 5.0/ A9L
Do you have any way to plug into the OBD port and monitor it while the engine is running? this would be SUPER helpful as you'll see if the O2s (and the signal they're reporting to the computer) are causing the computer to try to go "richer" or "leaner" (by looking at the "trim" numbers). That helps you adjust things like fuel pressure to get the computer to be "happy"Originally posted by cantvalve16
try to find a cheap palm pilot logger or something to monitor what the computer is seeing. Not just a code scanner, but a logger - the logger will show you codes and allow you to clear them, but more importantly it'll show you if all your sensor inputs are working (temps, TPS, MAP, O2s)www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!Comment
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Re: EFI troubles with 5.0/ A9L
Scanners, such as the old Snap-On MT2500, MAC Mastertech, Tech 1, all of these
are out here, and can do some real time scanning(like a GM), which will allow
you to see 02 activity.
Likely AZ or someone in your area could scan it for you,
in their parking lot.
You will be looking for the 02 to switch above and below .5v.Comment
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Re: EFI troubles with 5.0/ A9L
Any way to just watch it with a volt meter? Maybe the signal to possitive and ground to negative? Would that work?Bakersfield, CA.Comment
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