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914World.com _ 914World Garage _ Throttle Body and Throttle Position Sensor

Posted by: Craigers17 Mar 1 2020, 02:26 PM

So I recently bought a 914 and have only driven it about 3 miles. The accelerator pedal is very sticky and unresponsive. Today I took off the pedal board and disconnected the throttle cable on both ends. I think the pedal is being restricted by the cable, so I intend on installing a new one. However, it seems the throttle mechanism on the throttle body is also very tight and unresponsive upon actuation and release. So, first issue, I think replacing the cable and possibly having the throttle body rebuilt might fix this issue.

Second issue, it actually idles pretty well, however, with the throttle cable disconnected, if I give it throttle manually, it immediately tries to die. Occasionally it will backfire, but rarely will it rev with rpm's increasing. I realize at this point it's probably to early to diagnose problems, but any idea if this could be a symptom of a faulty TPS or throttle body?

On a side note, but more disturbing, is that while troubleshooting this whole situation, I took off the air cleaner and found it to be rusty and wet....the filter was soaked. So I've put the situation on hold for now while I clean up the air cleaner housing and get a filter.

Any input on any of this would be welcome....obviously I'm no mechanic, but don't let that stop you from making me feel like a dumbass...especially for not checking the air filter first thing. I've enclosed some pics of the pedal area, throttle body, and plenum area.
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Posted by: Mikey914 Mar 1 2020, 02:32 PM

Good news is it runs. Good call on cleaning up the intake system.
Im sure you can clean the throttle body too. It should help make it move much easier.
Get a rsin tray, or fix the one you have they are not too expensive if you need one.
#1 rule of the 914 keep water out.
You are in the right plave if you need to ask more questions.

Posted by: rhodyguy Mar 1 2020, 02:34 PM

That filter housing is pretty bad. I'd just get a dif one.

Posted by: rjames Mar 1 2020, 03:32 PM

I'd remove all of the stuff on top of the engine, clean the bits you can clean, tb, plenum, intake runners, etc. Then replace all of the hoses.
I'd also pull that pedal cluster and rebuild it. If you have a workbench with a vice, it's a fairly easy project. Then get new throttle and clutch cables because it's probably not long before they snap.

Congrats on a running car right out of the gage!

Posted by: Craigers17 Mar 1 2020, 03:40 PM

QUOTE(Mikey914 @ Mar 1 2020, 03:32 PM) *

Good news is it runs. Good call on cleaning up the intake system.
Im sure you can clean the throttle body too. It should help make it move much easier.
Get a rsin tray, or fix the one you have they are not too expensive if you need one.
#1 rule of the 914 keep water out.
You are in the right plave if you need to ask more questions.


Got a few other parts I need from you. Good call on the rain tray... I'm gonna order one of your kits tonite. Thanks!

Posted by: Craigers17 Mar 1 2020, 03:44 PM

QUOTE(rjames @ Mar 1 2020, 04:32 PM) *

I'd remove all of the stuff on top of the engine, clean the bits you can clean, tb, plenum, intake runners, etc. Then replace all of the hoses.
I'd also pull that pedal cluster and rebuild it. If you have a workbench with a vice, it's a fairly easy project. Then get new throttle and clutch cables because it's probably not long before it snaps.

Congrats on a running car right out of the gage!


I had a feeling someone was gonna bring up removing all the stuff on top of the engine...it kinda looks like there might be some rust and grime in the plenum. Thanks for the advice.

Posted by: Mikey914 Mar 1 2020, 03:52 PM

The pedal clusters are somewhat easy to rebuild. However, I’d the clutch arm is rusted into the end (there is a roll pin you have to drive out also), it can be an uphill battle. I have exactly this issue and decided to just get one of Bruce’s rebuilt ones. You will want to evaluate the assembly, you may only need to replace the throttle cable arm bushings. Have those if you need them. Check the pedal to make sure the hinge isn’t broken, but it all can b3 replaced or repaired, takes time and patience hopefully for not a lot of dough.

Hit me up if you can’t repair the throttle body.

Mark

Posted by: DRPHIL914 Mar 2 2020, 09:31 AM

QUOTE(Craigers17 @ Mar 1 2020, 04:44 PM) *

QUOTE(rjames @ Mar 1 2020, 04:32 PM) *

I'd remove all of the stuff on top of the engine, clean the bits you can clean, tb, plenum, intake runners, etc. Then replace all of the hoses.
I'd also pull that pedal cluster and rebuild it. If you have a workbench with a vice, it's a fairly easy project. Then get new throttle and clutch cables because it's probably not long before it snaps.

Congrats on a running car right out of the gage!


I had a feeling someone was gonna bring up removing all the stuff on top of the engine...it kinda looks like there might be some rust and grime in the plenum. Thanks for the advice.


sent you a PM, I have all those parts if you need non-rusty ones, all except for the throttle body but you can clean that up and rebuild it orhave someone do that for you. Mine looked like that when I first got the car too. Not really that hard, just lots of clean up and get rid of the dust, rust , all new seals which 914rubber has, check all that wiring and the grounds too!

Phil

Posted by: Craigers17 Mar 8 2020, 06:54 PM

So today I took the advice of some members, removed the engine lid, engine insulation pad, removed the injectors, and took off the runners. Didn't have time to remove the plenum yet. I haven't had time to clean anything yet either, but I do have a few more questions.

Turns out I have 2 green injectors, 1 yellow, and 1 gray/black. I have a 2.0, so I think green is correct. Ideally, I'd like to replace all 4 and keep the 2 existing greens as spares. Anyone know a good source for green injectors?

Second question...would it be correct to assume that the small black wire going thru the tin in front of the #3 cylinder plug is the head temp sensor? If so, is this the wire that ultimately goes to the temp gauge on the center console?

Finally, I've read a couple of places to replace the injector seals...I'm assuming those come w/ new injectors? Sorry for the stupid questions, but I've never taken these bits apart before.

Also included some gratuitous pics of the area below the engine lid pull cable. It looked really bad, but after just mild cleanup, the rust isn't as bad as I thought. I'll need to wire brush it at a minimum, but I think it will clean up.

Thanks for the help.

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Posted by: wndsrfr Mar 8 2020, 07:43 PM

An item to note since you disconnected the throttle cable is that when you re-attach it, be careful that it's not looped under or over the clutch cable down in the tunnel--very easy for that to happen and it causes quite a drag on the throttle pedal ....you'll need to remove the little inspection plate at the front of the tunnel & use a mirror to be sure that it's free....

Posted by: Craigers17 Mar 9 2020, 04:27 AM

QUOTE(wndsrfr @ Mar 8 2020, 07:43 PM) *

An item to note since you disconnected the throttle cable is that when you re-attach it, be careful that it's not looped under or over the clutch cable down in the tunnel--very easy for that to happen and it causes quite a drag on the throttle pedal ....you'll need to remove the little inspection plate at the front of the tunnel & use a mirror to be sure that it's free....


Thanks for the advice. The "drag on the throttle pedal" is what started this whole thing. Both the cable and throttle body are very "sticky"....somehow one thing has lead to another and here we are.

Any thoughts on the head sensor wire or where it ends up? Or a good supplier for the green injectors?....from my reading, Bosch has discontinued these.

Thanks!

Posted by: BeatNavy Mar 9 2020, 06:08 AM

Yes, that wire coming out of the grommet on the tin next to cylinder #3 is the CHT wire. Must be plugged into the right connection on the fuel injection wiring harness. Car won't run without that correctly functioning and plugged in (it immediately floods). I don't know if that was used as the temp gauge on some cars. I don't think so, and mine never came with a temp gauge. I run an aftermarket gauge with sending unit under spark plug #3 (but of course I still have a CHT).

Yes, if you have a 2.0 you need green injectors. Yellow ones are for 1.7L. Not sure about grey / black (EDIT: black are equivalent to yellow, 1.7L). The green ones are NLA, but if you put a WTB in the classifieds someone may answer. There are also some other injectors people are using as a credible replacement, I believe. Do a search here to see what comes up. Also, do yourself a favor and send all of your injectors to https://www.mrinjector.us/ to get them serviced and cleaned. He may actually send them back with new seals (IIRC).

There are two "o-ring seals" per injector. One, small one, that goes near the business end and seals it to the head. Then there is a larger one that seats the injector in the hold down clamp. You need both, and they are easily available at Pelican, 914Rubber, etc.

I haven't kept up with the post, but when I replaced my throttle cable and rebuilt my pedal cluster a few years ago it made a world of difference.

Posted by: Craigers17 Mar 9 2020, 10:46 AM

Rob,

Thanks so much for the info. That's exactly what I needed. I too am hoping the throttle cable replacement and throttle body re-build are going to make all the difference. Thanks again!
-Craig

Posted by: djway Mar 9 2020, 10:38 PM

I have been reading about AFM, injectors and CPUs for past several days.
Injector flow rates
https://motorwestperformance.com/fuel-injector-flow-rates-and-specs/
https://www.motormanfuelinjection.com/Fuel_Injector_Flow_Rates.html
Interchangeable parts (parts same on 914, Bus and Bugs often) List brains, afms, injectors
https://ratwell.com/technical/FISwap.html
Which injectors can exchange with which
https://ratwell.com/technical/Injectors.html
Ratwell is missing one part #which is 0 280 150 102 which is the same as 0 280 150 112 and 022-906-031C . I have a bunch of gray injectors that have 102 on one side and 031c on the other. I have found those 3 part #s listed for 914, Bus and Bug.
There is a wealth on information in the links provided above.
Enjoy the brain freeze:)

Posted by: Craigers17 Mar 10 2020, 03:33 AM

QUOTE(djway @ Mar 9 2020, 10:38 PM) *

I have been reading about AFM, injectors and CPUs for past several days.
Injector flow rates
https://motorwestperformance.com/fuel-injector-flow-rates-and-specs/
https://www.motormanfuelinjection.com/Fuel_Injector_Flow_Rates.html
Interchangeable parts (parts same on 914, Bus and Bugs often) List brains, afms, injectors
https://ratwell.com/technical/FISwap.html
Which injectors can exchange with which
https://ratwell.com/technical/Injectors.html
Ratwell is missing one part #which is 0 280 150 102 which is the same as 0 280 150 112 and 022-906-031C . I have a bunch of gray injectors that have 102 on one side and 031c on the other. I have found those 3 part #s listed for 914, Bus and Bug.
There is a wealth on information in the links provided above.
Enjoy the brain freeze:)


Thanks for the links! There is definitely a lot to take in there. Unfortunately, unless I missed something, only the first link gives much info on Bosch p/n 0 280 150 019, which is the OEM p/n for the 73/74 914 2.0, which corresponds to 039-906-031A.

Two of these can be had right now on Ebay for between $330 and $400 EA, but I'm not paying $750 w/shipping for 2 fuel injectors. I guess I'm just cheap. I have done some research online, and found that AutoZone, ....yes AutoZone, appears to have an aftermarket injector made by GP Sorensen that actually is specific to the 73/74 2.0. It makes me, at least assume, that it will have the correct flow rate because they have other injectors for the 1.7/1.8 as well. I found this brand mainly due to an old post here back in 2005 where a user said he was running these on his 2.0. And, I can have them next day according to their website at $84.99/EA - 3yr warranty. P/N is 800-1061N for the 73/74 2.0 version.

I'm going to give a set of these a chance....I'm interested if more people out there have tried these out? I should probably start a new thread on this as it really has nothing to do with my posting topic. Thanks again for the links....more info is always better!
-Craig

Posted by: djway Mar 10 2020, 10:41 AM

deleted fat thumbs

Posted by: ClayPerrine Mar 10 2020, 10:59 AM

QUOTE(djway @ Mar 10 2020, 11:41 AM) *

That part number you provided is from the 3.2 Carrera.


The autozone part number is 800-1061N. It is definitely a green D-jet injector.

https://www.autozone.com/fuel-delivery/fuel-injector/gp-sorensen-fuel-injector-800-1061n/80111_594834_0

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