Took the 4.9 to the dyno today......

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Fast88Fiero
Posts: 349
Joined: Sat Nov 20, 2004 12:18 am
Location: Michigan

Post by Fast88Fiero »

S8n wrote:
Fast88Fiero wrote:Figured out some of my problems today! Had a bad wire to the TPS and MAP sensors, they had too much resistance. Replaced the wires and it started running better. I also found out that I'm only getting about 11.8V to the fuel pump due to excessive resistance in the fuel pump relay. I'm installing a new relay tomorrow. :thumbleft:
Always good to figure out problems! Nice numbers also... When you get good 14 volts to the fuel pump, you're gonna run even richer though.
It's running leaner now since I fixed the TPS and MAP sensors. It idled smoother and had more power at higher RPM when I supplied charging voltage to the fuel pump at work. I'm thinking the pump doesnt have enough flow right now and the PCM is trying to make up for it by lengthening my injectors pulse width. After giving the fuel pump full voltage I watched my injector pulse width get smaller and my idle started to smooth out.
S8n
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Post by S8n »

That makes sense. Was it going to closed loop after you fixed the wiring?
-Chuck
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'87 GT *Now can be seen at V8Archie's!* www.fotki.com/8balls
Fast88Fiero
Posts: 349
Joined: Sat Nov 20, 2004 12:18 am
Location: Michigan

Post by Fast88Fiero »

Sure was. I rewired the fuel pump today and all is well. It's running much better, has more power at higher RPM's and feels like it has more power. Will have to get it back to the Dyno in the next couple of weeks. :thumbleft:
fieromadman
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Post by fieromadman »

Just because he is pumping more fuel doesnt mean that there is more fuel going into the engine.

Nice numbers!
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The Dark Side of Will
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Re: Took the 4.9 to the dyno today......

Post by The Dark Side of Will »

Lol... 3.5 years after the fact, this thread was linked on the "other forum".

Tunercat has had the definition files to tune the 2240 ECM (stock on 4.9) for a while now...

http://www.tunercat.com/tnr_desc/ecm_sup.html#cadillac
http://www.tunercat.com/
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