GM350 TBI hesitates when accelerating fast...

[fmt2bx]

Beware of buying from Amazon

Ah. Thanks Where would you get it from?

 

[alldodge]

Amazon can be used but need to verify what company is actually selling it. There are several out there that just clean used ones and sell, same as with ebay

Get from a company like Summit Racing, Napa, GM others

 

[fmt2bx]

Amazon can be used but need to verify what company is actually selling it. There are several out there that just clean used ones and sell, same as with ebay

Get from a company like Summit Racing, Napa, GM others

Thanks. Yeah I have had good luck with Summit Racing.
Of course our host is another good place.

 

[ChrisCraftFan]

fmt2bx, In one of the posts I think it said you replaced the regulator on the TBI body? If so, did you keep the old spring or use a new one? I think the new ones are at 11-13 psi and the original would be for 30 psi. Just throwing and idea out there.

 

[fmt2bx]

fmt2bx, In one of the posts I think it said you replaced the regulator on the TBI body? If so, did you keep the old spring or use a new one? I think the new ones are at 11-13 psi and the original would be for 30 psi. Just throwing and idea out there.

oh Boy!!!!!! Good point. I ll have to look in my rebuilt kit, see if I replaced the old spring.. Geez, that would be unfortunate if I did replaced it and threw it away. :-/


*******Edited to say that the spring wasn't replaced, it wasn't part of the rebuilt kit. So the old spring still in there)*****

 

[fmt2bx]

I did a bit more troubleshooting yesterday. weather isn't cooperating and it's only going to get worse from now on. I just wanted to re check a few things.

- Compression on all 8 cylinders around 130 psi
- The motor is equipped with a MEFI 1 ECM. I used the manual to check the timing and I need some clarifications on a few things if someone could help.

Motor ran til operating temp achieved.
With ECM in normal mode:
Motor running at idle 650 RPM, the timing is jumping from 4 btc to 8 btc (?)
Motor running , 1200 RPM (as per manual) and Timing is at 8 BTC steady.

With ECM in base timing mode (jumper between A and B of DTC plug)
Can't start the engine, cranks but no start unless I advance the throttle ( not sure if that's normal, manual doesn't mention).
Once started, rev to 1200 RPM and timing is at 4 BTC steady.
So my question is : Should the timing be set at 8 BTC in base timing mode?
If so, could 4 deg difference have such a big impact on how the motor is running when under load?
In base timing mode the motor quits when I get close to idle.(?)

Started to read about the IC module, MAP and TPS troubleshooting flow charts in the manual. Some of it can be done without the engine running some can't. So i'll have to wait for nicer weather.

Anyway. Got fuel pumps on order, I ll get that replaced.

Thanks

 

[alldodge]

Motor should be running and DLC without a jumper. Once normal operating temp is reached, place jumper in DLC without stopping the motor. with motor is base timing mode, adjust timing to 8 BTDC.

With timing adjusted and motor still running, remove jumper from DLC

http://boatinfo.no/lib/volvo/manuals/md_elect.html#/16

 

[fmt2bx]

Motor should be running and DLC without a jumper. Once normal operating temp is reached, place jumper in DLC without stopping the motor. with motor is base timing mode, adjust timing to 8 BTDC.

With timing adjusted and motor still running, remove jumper from DLC

http://boatinfo.no/lib/volvo/manuals/md_elect.html#/16

Thank you.