89 Ranger 2.9 auto won't rev past 1500 when warm

Z3CHYD · May 3, 2012

I was on my way to get my recently aquired 89 Ranger 2.9L Auto inspected and on the way it felt like it was losing power going up hills, until I had it floored and the engine wouldn't go past 1500rpms. At first I thought it was the trans taking a dump on me, but when I put it in neutral and tried to rev the motor same thing; wouldn't rev past 1500rpms. When cold to about 10ish minutes after it runs perfectly without a problem. Only thing that comes to mind is a bad/going bad ICM (Ignition control module) located on the disty. Any help guys? This was supposed to be replacing my other ranger, but not until this is solved. Thanks in advance!!

jhammel85 · May 3, 2012

You can probably swap the TFI modules between the 86 and your 89 to see if that's it. Use Dielectric grease if you do!

If not, Check the cap, rotor wires and Spark plugs. If the trucks been sitting for a bit, it might be worth a tune up. That said, maybe even bad, old gas but I think it's ignition.

Z3CHYD · May 4, 2012

jhammel85 said:
You can probably swap the TFI modules between the 86 and your 89 to see if that's it. Use Dielectric grease if you do!

If not, Check the cap, rotor wires and Spark plugs. If the trucks been sitting for a bit, it might be worth a tune up. That said, maybe even bad, old gas but I think it's ignition.

Yea the cap rotor wires and plugs were supposedly changed last year I don't think its them, it had almost no gas in it when I got it it's running on fresh gas now. I might have to give swapping the modules a try to see like you said, now I just have to see how "easy" it is to swap them, haven't taking one off a 2.9 since 2006 I'm a little rusty lol

jhammel85 · May 4, 2012

It's not bad just make sure to use the correct socket (7.7mm?) or the TFI tool you can get for a few bucks at an auto parts store.

I had the wonderful surprise of stripped bolt heads on my truck when I got it. I had trouble getting it to grab the 1st time I tried so I looked at it with a makeup mirror and found the heads to be stripped.

it was annoying since I had to remove the distributor. 5 minute job took an hour or two :annoyed:

Z3CHYD · May 4, 2012

jhammel85 said:
It's not bad just make sure to use the correct socket (7.7mm?) or the TFI tool you can get for a few bucks at an auto parts store.

I had the wonderful surprise of stripped bolt heads on my truck when I got it. I had trouble getting it to grab the 1st time I tried so I looked at it with a makeup mirror and found the heads to be stripped.

it was annoying since I had to remove the distributor. 5 minute job took an hour or two

I didn't have to remove the disty, just some fanagling with my hands in the right spot, I used I think it was 7/32's? deep well socket to get the old TFI off, I threw one from a 93 2.3 auto topaz on and wouldn't you know it works, drove it for half an hour, drove into town and got gas in er, drove home without incident, I think that was the problem, I'll update again if it happens again lol

Z3CHYD · May 12, 2012

Ok so update. The used tfi module went bad, or so I thought, so I put a brand new one in, still does the same thing. Won't go past 1500rpm when warmed up, barely makes it up hills/any kind of incline. Also I can hear popping in the intake when I have it floored trying to make it go. So still something electrical I'm guessing, since it can't be fuel, runs perfect when cold, and ran perfect for the 3 days i first replaced the stock tfi, maybe the pickup inside the disty? oh I hope not

Z3CHYD · May 13, 2012

Any ideas? would love to get this thing back on the road

a31ford · May 13, 2012

See My Post "FYI 88-91 Ranger Sensor Wiring...." This sub-group.

FWIW, I'm having about the EXACT same problem as you (That is the reason for the FYI post), Anyhow, Mine is about 2200 RPM.

NOTES about my findings:

1) I lost my exhaust about 5 days ago, AND, with no Muffler, what I can hear of the engine is this, when it starts to "do it's thing" (the 2200 rpm thing) it sounds like the engine is "motorboating" (kids in the tub, kinda thing... stick your tongue between your lips and blow), IF I can get it without a laod to 4000 Plus RPM, the problem goes away for a bit, but comes back once rev's go below 3000.

2) Sensors, I've replaced everything except the speed sensor (and I really thing it's not a problem or related to this.)

3) Diagnostics, The three BIGGEST sensors are (in order of importance) Air Charge Temp. MAP, Coolant Temp, TPS, TFI.

BUT, IMO, my issue is a bad computer (will be getting a new one this week.

Greg

Z3CHYD · May 13, 2012

a31ford said:
See My Post "FYI 88-91 Ranger Sensor Wiring...." This sub-group.

FWIW, I'm having about the EXACT same problem as you (That is the reason for the FYI post), Anyhow, Mine is about 2200 RPM.

NOTES about my findings:

1) I lost my exhaust about 5 days ago, AND, with no Muffler, what I can hear of the engine is this, when it starts to "do it's thing" (the 2200 rpm thing) it sounds like the engine is "motorboating" (kids in the tub, kinda thing... stick your tongue between your lips and blow), IF I can get it without a laod to 4000 Plus RPM, the problem goes away for a bit, but comes back once rev's go below 3000.

2) Sensors, I've replaced everything except the speed sensor (and I really thing it's not a problem or related to this.)

3) Diagnostics, The three BIGGEST sensors are (in order of importance) Air Charge Temp. MAP, Coolant Temp, TPS, TFI.

BUT, IMO, my issue is a bad computer (will be getting a new one this week.

Greg

Yea mine originally it wouldnt go past 2000, then it went down to 1500, and idle is 500, absolutely no power going up hills when doing so, the original TFI that was in there must of been a contributing factor, but not the main problem because it would shut off when i stopped having my foot on the gas, whereas the new TFI module i put on keeps it idling, just no power and never above 1500rpms when warmed up. Let it sit for a few hours and it'll drive just fine rev to anything....until it's warmed up again that is

Z3CHYD · May 18, 2012

n_grimm · May 18, 2012

You may have already checked these things but have you put a timing light on it when it's acting up to see if the timing is advancing like it should? Maybe a bad spout connection from the ecu if the timing isn't advancing. Also how about the fuel pressure when warm? If the rear pump quits intermittently the engine will run off the front pump on flat ground but not on the hills. Bad connections can definitely be affected by temperature due to expansion and contraction.

Z3CHYD · May 22, 2012

n_grimm said:
You may have already checked these things but have you put a timing light on it when it's acting up to see if the timing is advancing like it should? Maybe a bad spout connection from the ecu if the timing isn't advancing. Also how about the fuel pressure when warm? If the rear pump quits intermittently the engine will run off the front pump on flat ground but not on the hills. Bad connections can definitely be affected by temperature due to expansion and contraction.

I know the entire in-tank unit was replaced about a year ago, I'll have to check timing like you said, so if it's not advancing, then it could be a bad ecu?

Psychopete · May 22, 2012

'86 doesn't have a functioning check engine light, but pulling codes will get you closer to what's going on. Run a KOER test when the engine is fully warm

customrangers1 · May 22, 2012

have you checked for plugged exhaust? sound like maybe a bad converter

Z3CHYD · May 23, 2012

customrangers1 said:
have you checked for plugged exhaust? sound like maybe a bad converter

That might of been it, I removed the exhaust after the 2 cats and after running down the road and putting home, the inside of the cats were red hot. I chopped them both off, it revs past 1500rpms when warm now, but it's torally gutless now, not to mention ungodly loud lol. Probably something to do with running out of the y-pipe and nothing else lol. I'll have to fab up some kind of pipe, of course it's the oval part were I cut

89 Ranger 2.9 auto won't rev past 1500 when warm

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