rbcsaver

Jeremy,

Nothin cause I posted it first.

bott63

Hey Fred~
I'm curious if the new HTS did the trick.... I've been chasing after a similar problem in my '85 Carrera (130k miles.) While my car doesn't actually stall or quit, or burp at 5k rpm, it will seem to bog out between 2800/3200 rpm. The drop in power occurs when driving mellow at maybe half throttle shifting at 3.5k Above and below that range, when the car does its bad behavior, the car runs strong. This problem is intermittent at best. Sometimes when hot, sometimes when cold... Sometimes not at all

I've gone through the usual.... Vacume lines replaced, new plugs, wires, cap&rotor, fuel filter, DME relay, HTS, O2 sensor, and the problem still is around... After all of this nonsense, my independant mech. swapped a DME from an '86 that works perfectly, and still no fix. Also, all ground wires were checked. There was slight resistance on the battery cables, so we put in new ones, pos & neg, and cleaned up the frame where the ground wire connection is made (minor corrosion.) Also removed the quick disconnect from the battery & replaced with OEM. After that, the problem was about 80% gone. It is returning though, and getting worse. Also swapped the airbox and MAF from the other good running Carrera, with still no improvement.... Fuel pressure is excellent, injectors flow tested with no problems observed... The HTS replacement was an OEM single pin connector. I read a Pelican thread that there is a beefier upgraded HTS 2 pin connector that might actually be a 930 part. Anyone know about that? I guess it's possible that I got a defective replacement HTS.... Or perhaps this is just the weak link in my car.

I'm running a K&N air filter, and read the other post that sometimes the oil on the element can pollute the MAF & intake, but I did try swapping the MAF to no avail... Also, I'm running with bypass pipe, no cat., but did that switch over 50k miles ago with no problem until recently... Also, I'm running an Autothority chip, but did swap in the original chip, but still no change...

Is there anything else I've missed?

Pat

84_Carrera

Check on the HTS being the culprit

I'm going to be playing with exhaust / Steve W chip soon, so I'm going to be replacing the O2 anyway. Symptoms are currently gone, however, and the car's running very well.

bott63

I stand corrected... No MAF on 3.2 It's an Airbox. Likelyhood of K&A Filter oil clogging a 3.2 intake is minimal, according to my mechanic. However, after one of his other customers installed one on his 996, his factory warranty was suddenly void... $1400 later, all his problems had been repaired...

I also had compression test and leakdown performed, and everything checked out perfect...

Considering trying a innovateMotorsport.com tuning system to hopefully diagnose more accurately the problem under driving conditions... And yes,my mechanic does have , and tried one of the factory DME diagnostic analyzer systems that piggyback the harness.... All systems showed normal, with no anomalies...

rbcsaver

bott63,
I can tell you from personal experience that the AFM sensor wire can easily be fouled by the oil from the K&N filter. Over zealous re-oiling and not letting the
carrier volatiles dry (the oil itself does not dry) can allow the incoming air also carry the oil. I disconnected the filter and sprayed "Air Intake Cleaner" directly
into the AFM. Instantly cured the idle search, misses and hesitation that I spent
alot of time and money chasing. I had also replaced fuel injectors, O2 Sensor, HTS, and more with improvements but never a cure until I used the intake cleaner. You can find it at the auto store next to carb cleaner, but it is different. Don't use carb cleaner.
regards,
Steve

bott63

Thanks for the quick reply and info Steve!!!

Did you suffer through this nonsense with your '84? How much spray did you shoot up in her? How long should you let it sit before starting, or should you start it up right away?? I will really be banging my head against the wall, if this was indeed the problem! Thankful for the correct advice though! I guess after 130k miles, it didn't hurt to replace all the items anyway!

Curiously Yours,

Pat

84_Carrera

Not sure how the 911 is MAF-wise (does the 84 even have a MAF?), but for other MAF cars w/ K&N's that are contaminated, removing the MAF for close-up work and cleaning with Electronic Parts Cleaner (Radio Shack, Autozone, etc.) has worked wonders for cleaning the exposed MAF filament for me before. Of course, I've also used things like Berryman's B-12 Chemtool Carb Cleaner to clean them successfully as well (again, not on P-cars).

rbcsaver

Pat,
I took the filter and housind off, statred it and sprayed the intake cleaner directly in while manually giving a little throttle. Same way we used to spray carb cleaner in before injectors. Took all of 20 mins and most of that was R&R of the filterand case for access to the AFM. Let me know if it works for you.
I used probably 1/3 to 1/2 can. I used "CRC brand Fuel Injector Air Intake Cleaner" and think I bought it at AutoZone.
regards,
Steve,

bott63

I actually removed the l-shaped tube above where the TPS is and the air box. Loaded up both sides with air intake cleaner, put it all back together, and said a prayer. Apparently God must have been on the phone, and didn't hear me... Took the car for about a 15 minute drive, and initially, it stopped the flat spot... When I was a block away, it started its rough spot again... I'm going to drive it the next 2 days, and then maybe give your method of running the engine while spraying a try! After all the fun exhaust smoke show was over, the car did run a bit better, which was encouraging.... Perhaps your method is a more effective way of cleaning??

rbcsaver

I'm not following how you did this. You need to spray the intake cleaner directly
into the AFM intake with the motor running probably 1-2 K RPMs because it is a contact cleaner.
Steve

bott63

Maybe I did do it wrong here.... I will try it again, just removing the airfilter housing, with motor running. Hopefully you meant 1000 RPM and not 10,000, as that would definitely lead to entirely separate issues :-P! By removing what I did, I was able to clean closer to the TPS. One more stupid question... Does the 3.2 have an Exhaust Gas Return (EGR) valve type of set-up? If so, where is it?

rbcsaver

Whoops typo 1-2 K at 10K it wouldn't hesitate anymore..lol. You'll want to run the rpms up at the throttle body by hand as you spray directly into the AFM.
Steve

bott63

OkeeDokee Steve... I'll give it yet ANOTHER shot tomorrow, and let you know how it goes....
Thanks agin for the input...
Pat

ian911

Pat,
I'm waiting with baited breath to see if this works for you. I have EXACTLY the same problem (part throttle hesitation between 2800 and 3200 rpm) with my 84 3.2 (140k miles). I have replaced the dme relay with no improvement. I have a new cylinder head temp sensor that I haven't yet installed. I was also considering getting a new airflow meter but haven't yet. If this cures your problem I will be ready to try it myself.
Ian
'84 911 targa
'87 928s4 5 speed

bott63

Hey Ian~

Just checked in and caught your message...

This time I removed the filter, and the filter housing - pretty easily done with a 10mm socket with a quarter inch drive & maybe a 6 inch extension. 4 bolts on the inside of housing, & one 10mm locknut on the outside... This will give you more access to the "Barn Door." With motor not running, I wet down the barn door, and it's axis hinge? and inside of the air box. Let it sit for a few minutes, then started the motor, and ran it 1-2k rpm's while spraying the intake cleaner directly into where the barn door is. Put a good half a can inside.... shut the motor down, put it together & took it for about a 5 mile test drive... Of course it overall ran a little rough at first, then after it seemed to clear out a bit... The rough spot now moved to a new location - 4k rpm... Drove a few more miles, and it calmed down a bit. There still is what seems like a"'Surge" issue still going on though right at 3k rpm. If I try to hold a steady 50mph in 3rd gear (~3k rpm) I feel an intermittent surge.... Must be on the right track though... Car sat all day today, so I didn't get to mess with anymore... I will be putting on about 150 mile this weekend though, so I'll let you know how it goes....

Are you running a K&N Filter Ian? If so, have you cleaned & re-oiled it yet? I'm getting this sick feeling that this might be the demon.....

Don't start "throwing money" at the car just yet... Check your maintenance records for the car, & see if the HTS has ever been replaced. If not, it wouldn't be a bad idea to replace it anyway. I had to replace mine right after I purchased the car at ~60k miles. It was for a completely different problem though.. At hard throttle, the car would actually completely cut out at about 5k rpm for about a half a second then start again slamming the crap out of the entire driveline. I only had to have that happen twice, before bringing it in to get serviced... Was a bad HTS...

I would strongly suggest the "Intake Cleaner" method to you... At 140k miles on your car, it certainly could use a little cleaning by now! It's cheap, and would probably not take more than an hour of your Saturday! That includes the drive to Napa, or AutoZone.... As I'm finding out, it might take several tries before complete success with this method.... If you notice ANY change at all after one try, you know you are on to something! You've really piqued my curiosity now.... I really want you to try the intake cleaner to see if YOU have any luck.

How do you like the 928 5-speed?
I'm selling my '70 911T, and was thinking of picking up a 928, but only if it's a 5-speed 87 or newer, ultimately a '91 a newer last series model...

Good Luck!

Pat