Intermittant miss at light load cruising only

[Blazer406]

First let me say that the car has pretty much sat with no engine and tranny since mid 2006. I got my engine ready and dropped it in recently. It seems to run pretty good, but I have one issue I can't pinpoint. I have an early version of turbotweak wideband chip. I am running type II coilpack and module that has worked fine in the past. Stock cam sensor and and crank sensor.

When out on the highway, cruising around 75 or so..... it sputters and misses intermittantly from time to time. You roll into the throttle a little and as the boost starts to roll from vacuum into boost.... and it pulls smooth as silk. Pull off a stop sign.... and it pulls fine.

On a more severe miss while cruising, it is like the converter unlocks and the SES light flasses for a split second...and then it is fine.

I have several underhood connectors not being used and a couple that could use replacing. The not used ones are:

1.) 2 connectors for the powermaster (I converted to hydroboost)
2.) wastegate solenoid
3.) EGR
4.) Inlet air temp (unused when you run a wideband chip)

My TPS connector has the tab broke/missing to keep it fully seated, although this has been like that for years. My injector harness connector on the firewall also has a broken tab that keeps it fastened securely. I currently have it taped up.

I am wondering if I am having an intermittant crank sensor issue.... or I have an electrical connector somewhere that has just gotten corroded and needs cleaning and put some of that dielectric grease in it.

Any ideas?

 

[jasjamz]

Sounds too lean in those areas. Try raising the fuel pressure 2-3 psi and see what happens.

 

[Blazer406]

Sounds too lean in those areas. Try raising the fuel pressure 2-3 psi and see what happens.

The wideband shows AFR's swinging while it is doing this. The chip does have a "lean cruise" feature. Some of the times while the lean cruise was kicked in.... I was getting AFR's around 16:1 and it was smooth as silk. The AFR was steady there too. The Scanmaster was showing around 72-100 mV during this lean cruise....and steady....

When it was sputtering...... the AFR's were flopping all over.

 

[TurboBob]

got any better data? The flicker of the check engine light sort of points to a chip issue. Try tightening the chip socket.

If the chip has a 'shift light' feature then a crank sensor issue could conceivably cause the flicker and a stumble.

PowerLogger or Direct scan data would assist troubleshooting.

Bob

 

[Blazer406]

Unfortunately no. I don't have a win 98 laptop at the moment..... so ds won't work. I have to get my new pl out and hook it up. I am going to drive the car to work in the morning....... 100 miles tomorrow will do it some good anyway.

 

[Blazer406]

Well.... made it to work today..... 50 miles or so.... 1 way.... still had the intermittant miss under light load. No SES light today.... that has actually only happened maybe twice in the 150 miles or so that I have driven the car since the motor was installed. It is like it coughs once and the wideband AFR seems to jump real lean during the "cough" then it comes right back where it should be. Maybe I will have a chance to locate my PL and hook it up soon.... hopefully have time this weekend to do some troubleshooting.

I keep going back to the crank sensor and how I set it.... I set it on the stand.... installed it in one of the windows and carefully rolled motor over away from one of the windows and by feeling... just put it in the middle and locked it down. There was literally no perceivable "slack" one way or the other before I tightened it down. I am wondering if using paper or something like that... to put it on both sides of the wheel therefore "theoretically" insuring it has a little clearance. I guess in theory... it could be almost touching since I only set mine by feel???

 

[TurboBuRick]

If I tell you what it is, will you buy me cheese burger? :biggrin:

RL

 

[Blazer406]

If I tell you what it is, will you buy me cheese burger? :biggrin:

RL

Sure.... you have to come get it in person...... J/K

Seriously.... I plan on maybe Sunday spending a couple hours with the car....me....a laptop.... and a powerlogger. I will prevail!

Anyway.... I am all ears if you have good ideas.....

I drove the car to work today...then after work took a couple Turbo Buick buddies for a ride. I let a guy with a 9 sec car drive it..... my tires will never be the same.... :biggrin: We all agreed.... that other than this stumble/miss/intermittent sputter ..... it sure does run good!

 

[Blazer406]

Well.... I did locate the boxes in my stash that had my new TT chip, my new 80# high z injectors, and the new powerlogger. Maybe I will get a chance to get the PL on it later this weekend and see what is up.....

 

[wilkinsde]

I had a similar problem a few years ago just after a rebuild with several goodies added including some new injectors. I'm not what you would call a real troubleshooter so we changed the coil pack and plug wires with another car that was available, along with some other items I can't remember. The intermittent miss went away when we put the original injectors back in the car. It appeared one of the new injectors was faulty.

 

[TurboBuRick]

Sorry man. I did not mean to leave you hanging. I been out plowing snow in a pay loader for last 24. Feel like I went 10 rounds with Tyson.

Anyway, 9 out of 10 times the cam sensor is the culprit. Run that sucker it in batch fire and see if it clears up. :wink:

Rick

 

[TurboBuRick]

Updates?

 

[Blazer406]

Updates?

Unfortunately no. I have the PL ready to go in and see what it says.... and my new chip... and my new 80# high Z injectors.... I should have some time this weekend as I will be around the house. I hope to put the PL in and try and figure out the miss before I change chips and injectors.

 

[jasjamz]

Recently a member found the cam sensor cap issue. Pull it off clean it check the ring and reassemble.

 

[TurboBuRick]

Recently a member found the cam sensor cap issue. Pull it off clean it check the ring and reassemble.

Usually the cap itself go's bad, the tab breaks or develops excessive up and down end play. Either way if it's old it's prolly ready to be replaced.

Very simple to test. Start the car. Unplug the cam sensor. Go for a ride.

Rick

 

[Grumpy]

Very simple to test. Start the car. Unplug the cam sensor. Go for a ride.

Rick

NO I would NOT do that !! Way to simple to try an fix.. What 5 minutes

 

[GNONYX]

Unfortunately no. I have the PL ready to go in and see what it says.... and my new chip... and my new 80# high Z injectors.... I should have some time this weekend as I will be around the house. I hope to put the PL in and try and figure out the miss before I change chips and injectors.

You claimed to have some few bolt ons, but never mention if you have a "hot-wire" installed in your car. If you are running a stock fuel pump it maybe that is finally breaking down, or also your fuel filter is starting to be clogging up.
Secondly, I have read some were in this great site, if going to larger fuel injector than 60# you will need a double pumper.
Check out Racetronix http://www.racetronix.biz/itemdesc.asp?ic=FI114961&eq=&Tp= for their 60# injector and a fuel pump set up http://www.racetronix.biz/itemdesc.asp?ic=FPS-G7W255&eq=&Tp= this may cost a bid more but their set up is already done for you, where as I have went a little cheaper (http://www.racetronix.biz/customkititems.asp?kc=FPA-015&eq=) but I had to put all the pieces together and change the wire configuration of my original wires. Last thing the "hot-wire" http://www.racetronix.biz/itemdesc.asp?ic=FPWH-006&eq=&Tp= G7 Fuel Pump Wiring Harness.

 

[Blazer406]

I think I found something!

I went to take the coilpack off....so I can swap the injectors...... and when I tool the coilpack electrical connector off.....I noticed one of the pin sockets on the wiring harness connector was not seated....it was pushed in probably 3/8". It could have easily not been making connection all the time....... it is a Gray wire with a red stripe......

Per my diagram....that is the wire that carries 12V to the cam sensor. IMHO, this could easily have been causing my stumble.

Will have to see tomorrow. Off to swap injectors now.....

 

[TurboBuRick]

no i would not do that !! Way to simple to try an fix.. What 5 minutes

lol!

 

[Blazer406]

You claimed to have some few bolt ons, but never mention if you have a "hot-wire" installed in your car. If you are running a stock fuel pump it maybe that is finally breaking down, or also your fuel filter is starting to be clogging up.
Secondly, I have read some were in this great site, if going to larger fuel injector than 60# you will need a double pumper.
Check out Racetronix Racetronix - L107 - 63 lb/hr Siemens High-Z Fuel Injector MT for their 60# injector and a fuel pump set up Racetronix - FPS-G7W255 - Fuel Sender, G7 SS w/255LPH Pump this may cost a bid more but their set up is already done for you, where as I have went a little cheaper (Racetronix - G77 Fuel Pump Assembly - Kit Configuration Page) but I had to put all the pieces together and change the wire configuration of my original wires. Last thing the "hot-wire" Racetronix - FPWH-006 - G7 Fuel Pump Wiring Harness G7 Fuel Pump Wiring Harness.

I do have some bolt-ons ......but currently.....at least for the short duration, I am only running a stock turbo......

FP is a walbro 340....not hot wired yet.....but it is on the list. I have also purchased one of the new aeromotive 340 pumps that will go on when I finally swap out the turbo and will hot wire it at that time.....

Fuel filter has been changed, but probably wouldn't hurt to change it again......

I did just swap over to 80# high Z injectors. Should be enough injector to go into the high 9's safely..... The single pump combined with the alky should also be capable of supplying enough fuel to get into the high 9's.

I'll eventually get there.....baby steps for now....