'86 GN- Motor breaks up (pops) at 5-10 psi of boost

[Randy Hagins]

My '86 GN has a problem with missing/poping at low boost, around 5-10 psi. ( TE44 boost set at 17 psi) Here is a run down of what I have changed out or noticed with the OTC. I changed out the coil pack, changed out my heated O2 sensor to a GNX type, Fuel pressure is 36 psi with vac on, 42 with off. Fuel press 62 wot. MAF shows 249-255 wot, Os volts @ 82 range. Volts between 13-15, I have a volt booster. Fuel filter changed last Oct. Plugs changed a week ago. The car acts like its out of gas. Not sure what else to check. Any help sure would be appreciated. If I can think of any thing else I have noticed or changed I will list it. thanks again for any input!

 

[jasjamz]

which plugs did you use and was it doing this before the plugs?

 

[TurboBuRick]

Does it clear up if you keep pushing it?

 

[TurboDave]

When did this start happening? IOW. Was there a change made to the car at about the time this started happening? Plugs alone should not have done it unless you got some wierd ones.

When you say you changed the coil pack, did you also change the ignition module under it? And were they KNOWN to be good?

Is your OTC in "Road Mode"???

 

[gn4u2c]

verify the coil is good seen new ones that are bad.. verify module, verify correct plugs if they are all good pull the valve covers cam could be wiped

 

[HelloBozos]

Check for cracked/loose Cam Senser cap an/or the unit it self loose from top water pump

Enjoy!

 

[Rodney87GN]

So at WOT it runs fine, but low boost it doesn't?

Maybe a dead spot in your TPS before it reaches WOT?

 

[Randy Hagins]

Autolite 24's. I have been using this type of plug for years with no problems.

 

[Randy Hagins]

I wont stay in the trottle long enough to see if it breaks up in high boost. Its bad, sounds like the car is out of gas.

 

[Randy Hagins]

I will chack that now, thanks for the input!!

 

[Randy Hagins]

Hope cam isn't wiped! oil pressure is good. How could lobe get wiped? Motor was rebuilt in '07 with a 206/206 cam. Pray it isn't that!!

 

[Randy Hagins]

OTC is in "road mode", I changed the plugs after I started having this problem. No other changes made to the car since 2009 when I put on a TE 44 turbo and changed tourqe converter. The car has ran a best of 12.30 @ 112mph. I did buy a ne module bacjk in 2006 and the old one worked fine, just wanted to change it out. I will put the old one back in, hope that is it.

 

[TurboDave]

It certainly sounds like the symptoms of a bad coil pack and/or module.

 

[HelloBozos]

Thought of another cause typicail to GN's...Your "sock" (fuel pump filter in the gastank) on your Fuel pump if it's stock an old may be "collapsing"..you keep saying feels like outa gas, Just may be it. I've whiped many a camshaft,you just loose power, no pops or cutting up, untill whipe it enough the hydrolic lifter can't compinsate,then get the "Taps"

Enjoy!

 

[Jerryl]

My '86 GN has a problem with missing/poping at low boost, around 5-10 psi. ( TE44 boost set at 17 psi) Here is a run down of what I have changed out or noticed with the OTC. I changed out the coil pack, changed out my heated O2 sensor to a GNX type, Fuel pressure is 36 psi with vac on, 42 with off. Fuel press 62 wot. MAF shows 249-255 wot, Os volts @ 82 range. Volts between 13-15, I have a volt booster. Fuel filter changed last Oct. Plugs changed a week ago. The car acts like its out of gas. Not sure what else to check. Any help sure would be appreciated. If I can think of any thing else I have noticed or changed I will list it. thanks again for any input!

Does it sound/act like this?

 

[hesermon]

Randy, try this: one at a time remove the plug wires and check each one with an ohm meter. I had same exact symptom, car ran perfectly at idle and during normal driving. As soon boost started to spool it would start missing badly. One wire showed almost no resistance on the meter, replaced it and problem is gone. Good luck!

 

[rob350]

Randy, try this: one at a time remove the plug wires and check each one with an ohm meter. I had same exact symptom, car ran perfectly at idle and during normal driving. As soon boost started to spool it would start missing badly. One wire showed almost no resistance on the meter, replaced it and problem is gone. Good luck!

I had the same problem and it turned out to be the plugs wires also! I kept trying different things to fix the problem and I couldn't figure it out. I never thought a had a bad plug wire, they were fairly new wires.

 

[slick6732]

Had a similar problem, turned out to be a crack in the wastegate hose!! Hope its that simple

 

[Randy Hagins]

Thanks for all the input. Just to answer some of the questions. I changed the fuel pump out in 2002 with a XP pump. I did not rule out the sock filter collapsing, will check that out for sure. I have a friend that will lend me his coil pack/module to see if that is the problem and I have heard that the wires could be bad along with every one that has listed the wire problem on here. Lets hope that is it. I am buying some this week. Might be a while until I get to work on the car again. What ever I find I will post on here. Thanks again for every ones input! has to be one of these issues that is giving me fits! Also, one more thing. I had the RJC boost controller on, took it off and put on Y hose. that wasn't it, wish it was.

 

[hesermon]

Thanks for all the input. Just to answer some of the questions. I changed the fuel pump out in 2002 with a XP pump. I did not rule out the sock filter collapsing, will check that out for sure. I have a friend that will lend me his coil pack/module to see if that is the problem and I have heard that the wires could be bad along with every one that has listed the wire problem on here. Lets hope that is it. I am buying some this week. Might be a while until I get to work on the car again. What ever I find I will post on here. Thanks again for every ones input! has to be one of these issues that is giving me fits! Also, one more thing. I had the RJC boost controller on, took it off and put on Y hose. that wasn't it, wish it was.

Do yourself a favor and before installing new wires check each one with the ohm meter. When I put on my new wires there was no difference in how my car ran so I assumed that since they were new that must not have been the problem. Much to my surprise one of the new wires tested bad on the meter, all I did was replace the old set with new wires, one of which being bad. Could not believe that one was bad right out of the box, I'll always check from now on.