1999 5.2 stalls after plenum repair

[dmckeehan]

Replaced the plenum, now truck will start and die. checked everthing twice, swapped IAC, map, and tps from running truck to this one, still same issue. restarted truck, everthing worked great. then we realized we had left the vacuum line off the brake booster, plugged it up, truck immediatly died. pulled line back off, restarted truck, it started and ran. plugged the vacuum line to the booster, immediatly died...... never seen an engine run better with a vacuum leak, than without one. Any suggestions?

 

[Pntyrmvr]

Did someone leave a rag in the intake?


"Talk is cheap. Whiskey costs money."

 

[dapepper9]

Can you keep it running with your foot on the throttle

 

[dudeman2009]

Of course it'll stall when you put the vacuum line on it at idle. The IAC needs a second to adjust, especially if its old or a cheap one.

Try starting the engine, giving it some throttle then put the line on. Give it a second then slowly let it down to idle. It has to 'learn' how the engine runs.

If you get it running and get the brake booster off, but it still won't idle after a few minutes, i'd look into that IAC.

These engines don't use MAF sensors, they use MAP sensors, they don't measure the flow of air, they measure air pressure. They can detect vacuum leaks very well, they can also compensate better at different altitudes than vehicles with MAF sensors because the MAP sensor takes a reading of atmosphere density before the engine is started in order to determine aprox. how much oxygen is available.

 

[dmckeehan]

got it back running, loosened the distributor, wiggled it back and forth a few times, (like adjusting the timing on an older motor) then tightened it back down and it started and ran great. thanks for the help guys!

 

[Shadow_Death]

Sounds like maybe bad points in your distributor cap?

 

[crazzywolfie]

got it back running, loosened the distributor, wiggled it back and forth a few times, (like adjusting the timing on an older motor) then tightened it back down and it started and ran great. thanks for the help guys!

if you had to mess with the distributor to get it running you need to see about setting the fuel sync. you can not just play with the distributor on newer trucks like the older ones. it may run but you may notice more issues caused by the fuel sync not being set correctly.