Trans or Engine problem? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jayschevy · 03-31-2013, 11:34 AM

I'm hoping someone can help me. I have a 71 350 5.7L V8 with a 350 turbo transmission. The problem I have is this. The truck starts fine and idles fine but when I put it in gear (drive) it bogs and tries to shut off. I have to keep giving it gas to keep it running. If I put it back in Park or in neutral the truck runs fine again.
Has this happened to anyone before? Anybody have any ideas?

msgdsrf · 03-31-2013, 11:37 AM

Is the idle set too low?

geezer#99 · 03-31-2013, 11:55 AM

Bump up your timing to at least 10-12 degrees!

msgdsrf · 03-31-2013, 12:34 PM

Quote:

Originally Posted by geezer#99

Bump up your timing to at least 10-12 degrees!

Yup check timing, this will also rasie idle.

**TBONE1964** · 03-31-2013, 12:39 PM

I would check also for vacuum leaks. Use a can of carb cleaner and spray around the base of the carb and around all of the vacuum hoses and base of intake. Do this while the engine is running at idle. If the rpm of the engine drops when you are spraying, you have a vacuum leak.

Do this with the air cleaner in place and try not to spray into the top of the carb. You should be able to isolate a vacuum leak doing this.

Jayschevy · 03-31-2013, 01:04 PM

I forgot to also say that when I put it in drive the truck jerks hard forward like it wants to take off. I have to keep my foot on the brake to keep it from moving forward and my foot on the gas pedal to keep the engine from shutting off.

oklalawnboy · 03-31-2013, 11:06 PM

I agree with Tbone. Check for vacumn leaks. If it's lurching forward I gotta guess idle is too high. OR maybe it's got a killer race cam and won't idle down....... check timing too

airdale94 · 03-31-2013, 11:58 PM

Your vacuum modulator on your trans. is bad. It's sucking trans. fluid into your engine.

msgdsrf · 04-01-2013, 09:31 AM

Quote:

Originally Posted by Jayschevy

I forgot to also say that when I put it in drive the truck jerks hard forward like it wants to take off. I have to keep my foot on the brake to keep it from moving forward and my foot on the gas pedal to keep the engine from shutting off.

Not a low idle then.

Unhook and plug the vacum modulator line at the intake manifold and see what happens.

Wrenchbender Ret · 04-01-2013, 09:34 AM

I would check the modulator but it sounds to me you have a bad Torque converter in the trans.

**Ol Blue K20** · 04-01-2013, 12:45 PM

Quote:

Originally Posted by Wrenchbender Ret

I would check the modulator but it sounds to me you have a bad Torque converter in the trans.

x2

cdowns · 04-01-2013, 04:36 PM

i would try to ride down the road for a long road trip and try and see what a prolonged test will tell/// minimum20-25miles

03-31-2013, 11:34 AM	#1
Jayschevy Registered User Join Date: May 2012 Location: Eastern, NC Posts: 429	Trans or Engine problem? I'm hoping someone can help me. I have a 71 350 5.7L V8 with a 350 turbo transmission. The problem I have is this. The truck starts fine and idles fine but when I put it in gear (drive) it bogs and tries to shut off. I have to keep giving it gas to keep it running. If I put it back in Park or in neutral the truck runs fine again. Has this happened to anyone before? Anybody have any ideas?

03-31-2013, 11:37 AM	#2
msgdsrf Registered User Join Date: Jul 2012 Location: White Salmon, WA Posts: 263	Re: Trans or Engine problem? Is the idle set too low?

03-31-2013, 11:55 AM	#3
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Trans or Engine problem? Bump up your timing to at least 10-12 degrees!

03-31-2013, 12:39 PM	#5
TBONE1964 Cluster King Join Date: Nov 2012 Location: Junction City, OR Posts: 5,263	Re: Trans or Engine problem? I would check also for vacuum leaks. Use a can of carb cleaner and spray around the base of the carb and around all of the vacuum hoses and base of intake. Do this while the engine is running at idle. If the rpm of the engine drops when you are spraying, you have a vacuum leak. Do this with the air cleaner in place and try not to spray into the top of the carb. You should be able to isolate a vacuum leak doing this.

03-31-2013, 01:04 PM	#6
Jayschevy Registered User Join Date: May 2012 Location: Eastern, NC Posts: 429	Re: Trans or Engine problem? I forgot to also say that when I put it in drive the truck jerks hard forward like it wants to take off. I have to keep my foot on the brake to keep it from moving forward and my foot on the gas pedal to keep the engine from shutting off.

03-31-2013, 11:06 PM	#7
oklalawnboy Registered User Join Date: Jan 2012 Location: Glencoe Alabama Posts: 510	Re: Trans or Engine problem? I agree with Tbone. Check for vacumn leaks. If it's lurching forward I gotta guess idle is too high. OR maybe it's got a killer race cam and won't idle down....... check timing too __________________ 72 Cheyenne super 10 08 3500 HD 4dr dually 12 ford flex (wifes ride) 76 Monte Carlo 83 Chevy short wide Silverado 96 Mazda Miata, 2000 Allegro Bus

03-31-2013, 11:58 PM	#8
airdale94 Registered User Join Date: Jan 2007 Location: Topeka,KS Posts: 778	Re: Trans or Engine problem? Your vacuum modulator on your trans. is bad. It's sucking trans. fluid into your engine. __________________ 68' C20. 283CI w/55CC 305HO heads, NP435 Close Ratio, Corp. 14 bolt FF 3.21, 75' front end swap (everything but the X-member).

04-01-2013, 09:34 AM	#10
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Trans or Engine problem? I would check the modulator but it sounds to me you have a bad Torque converter in the trans.

04-01-2013, 04:36 PM	#12
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Trans or Engine problem? i would try to ride down the road for a long road trip and try and see what a prolonged test will tell/// minimum20-25miles __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.