Testing Fuel Pumps

I have a Dave Helms modded board and was wondering if there is any way to manually test the fuel pumps? Also, read about testing the red wire for +12v at the water thermos witch by jumping from the starter to the blue/white wire which should also engage the fuel pumps, I've tried this with no success

any suggestions would be appreciated.

Jeff

 

Did you have the key "on"?

 

you may jump the fuel pump relais ( so terminal 30 and 87 ) to test the pumps

 

Ok key "ON" was able to confirm +12v at the red wire and both fuel pumps do operate. Completed the major service this spring and set the car up as per the WSM and some help from a few f-chatters. Car was perfect, balanced with manometer, exhaust gases confirmed with O2's unplugged and plugged, set up idle with timing light as my tach is another issue! Cold start was perfect and life was grand. Drove the car for a month no issues. One day driving for about 90 minutes stopped for 30 minutes went back and car hesitated when trying to restart. After a few attempts it fired up but could definitely hear a high pitched buzzing which I assumed was a fuel pump. Was able to drive home with no issues. Now car will start cold and run like it should for the first 8-10 seconds and the tach reads 1k which is where we set it, then the idle noticeably drops a few hundred RPM and the tach drops to 0. Something has changed! But instead of just randomly buying a bunch of new parts I'd like to run some tests first.

I have done a few tests, confirmed the RPM flywheel sensor is 2.4 VAC with engine running, have +12v at the red wire on the water thermoswitch and both fuel pumps do turn on with no buzzing! Have not check the flow or output of the pumps will do that in the next few days.

Any suggestions are appreciated.

 

Have you confirmed/denied if you have spark on both banks?

 

Yes confirmed spark on both banks while running. Started it again this morning and same result fires right up runs strong for maybe 10-15 seconds right at 1000 rpm then idle drops to 800 rpm tach stops registering and she smells rich. If i blip the throttle she will hunt but not stall.

 

Cold starting at 1000 RPM is a bit lowish unless you are here in TX during the summer

Are you saying this is a three-step process: 1000 RPM on tach, drops to 800 RPM on tach, then no tach, but engine keeps running the whole time

or is it only two steps: 1000 RPM then tach stops working, but engine keeps running, and you are just estimating it being at ~800 RPM when the tach is not working? Or please reclarify if I don't have it yet.

What "with red wire" version TR: US (F113A040 engine) or euro (F113B engine)?

 

Ok sorry
* F113A040 Engine
* Dave Helms Fuse board upgraded 3 yrs ago
* Dave Helms gold connector kit upgraded 3 yrs ago
* +12v on the Water thermoswitch red wire while engine running
* Cats have been removed but O2 sensors still in place
* Air pump removed a few years ago as per this post
https://www.ferrarichat.com/forum/boxers-tr-m/318293-removing-secondary-air-pump-lines.html
Car starts from cold and settles around 1k RPM as per the tach ( can verify exactly RPM but other timing light is at the shop will get tomorrow)
Car runs for approximately 15 seconds +- 5 seconds and then simultaneously the tach needle drops to 4-5 hundred and the engine idle drops to what I am guessing as 800 RPM
After another few seconds the tach needle drops to 0 but the engine idle remains unchanged to what I am guessing as 800 RPM
Like I had mentioned and I must clarify, I am no expert by any means, but after we set up the Idle and A/F mixtures this spring after completing the major service the car started cold or warm perfectly and idled smoothly, put on approximately 500 miles. Then after driving one day and trying to start it this problem began.

 

Could it be the auxiliary air valves (cant think of the actual names) that are in front of the throttle bodies? When cold, the spring opens a disc with a hole in it, allowing more air in when cold. As the engine warms up, the spring inside expands and turns the disc until the hole is closed. I dont know how lomg it takes to be warm enough though but maybe theyre stuck open or a vacuum line came off?


Sent from my iPhone using Tapatalk

 

Running a few more tests this morning checked all fuses and connections again at fuse panel.
Pulled the tachometric relay and tested as per post 7 in this thread. https://www.ferrarichat.com/forum/boxers-tr-m/288552-tr-fuel-pumps-do-not-run-when-starting.html

Results were;
Test 1 "key off" +12v between terminal 30 and 31
Test 2 "key on" +12v between terminal 15 and 31
Test 3 "starter motor cranking" +9.5v between terminal 50 and terminal 31
Not sure if the +9.5v is a problem or not?

 

No, it's not a problem (the reason the battery voltage droops down is that you are drawing ~200A out of the battery to run the starter). The only function of the tachometric relay is to close the fuel pump relays and run the fuel pumps -- if the fuel pumps are running = nothing wrong with the tachometric relay.

Have to say your symptom still smells of one bank not running, but the tach not reporting at all when the engine is actually running is not a good sign. When you said that you confirmed spark -- are you using a timing light directly on a single cylinder in each bank during the "engine running slowly and tach = 0" operation?

 

Yes checked each plug wire actually and all 12 have spark while engine is running and tach reads "0". I can make the tach work if I turn on the headlights and play with the rheostat in the centre console that controls the interior dash pod lights. A few have suggested a poor ground but I've been looking and testing all the connections and haven't found one yet. I think I also mentioned a few posts back that my tach should work as the board was replaced by Moma and I was assured it was bench tested and functional. I've also read a bunch of your post regarding the food chain for the tach signal from the flywheel sensor and would like to keep digging and testing before I panic and S*#t my pants if it is the ignition ECU. I know its frustrating with my terrible description, kinda like my patients never really able to describe what exactly they feel when their shoulder hurts but with enough questions and tests we usually figure it out . I will post up a video later tonight or tomorrow so you can see and hear exactly what I'm trying to covey! Thanks for your help thus far.

 

any update? Is the problem fixed? If so what was the problem? (I am currently having some issues with right bank no spark and after swapping coils the fuel pumps don't work. (coils back to original configuration)

 

Hi Fred,

Problem not solved yet and haven't had the time to get back to the car recently but I did find a few issues that needed to be addressed.

1. Throttle micro switch was not properly closing so readjusted as per this post
http://www.ferrarichat.com/forum/boxers-tr-m/266918-how-microswitch-setting.htm

2. Re-confirmed resistance on all 12 plug wires found plug wire number 3 was not securely fixed in the distributor cap so fixed that

3. I had replaced the vacuum lines from the t-connector to the 7-12 intake manifold mainly for aesthetic reasons along with new newco clamps. While running the car I just happened to notice that the new 12mm id hose I had sourced from a Canadian vendor was collapsing on itself. I have since replaced the hose with a mercedes hose that is wire reinforced. I also never considered testing the check valve (#5) when I removed it, I don't think this was functioning very well so cleaned it and it appeared to function with a lot less pressure.
http://www.ferrarichat.com/forum/boxers-tr-m/308985-need-part-170956-vacuum-pump-3.html

4. The last time we ran it a mechanic friend said it sounded like there might be a vacuum leak at the 7-12 throttle body gasket so grabbed his smoke tester and will play with that after Christmas.

5. As for the tach well that one still has me stumped! But will continue to test a few of the input signals etc.

I am kind of on my own up here in the middle of the country not many options for Ferrari mechanics I'm wondering if the vacuum hose just took a few miles to collapse and that's why it appeared to run OK for the first little while this past spring after we tuned the car. I also thought the car started and ran ok at cold start but looking back now I do remember from cold start it would surge up and down quite significantly, wonder if the microswitch adjustment will fix that.

I did reach out to a few f-chat members and they were all great with their suggestions on things to look at and test. I am by no means a mechanic but do have a great group of car guys to give me a hand.

If I can't get it sorted this winter I'm only 8 hrs from Minneapolis where F-chat member 2NA (Tim) is located, he has been very kind with offering a few suggestions, so putting the car in a trailer is the next logical step.

Open to suggestions if anyone wants to comment!

Happy Holidays!

 

I would unplug/replug both ECU's and the connections under the expansion tank. Then maybe unplug the O2 sensors and start her up, see if the issue occurs....grasping at straws here but it's worth a try...

 

Mine is an 86 , K-Jet, I have the Dave Helms Fuse box fix. Unplugged and replugged the connections under the expansion tank. The fuel pumps don't start up. I will do some tests with the tachometric relay soon.

 

Well the KISS principle wins again to some degree. Had some time to spend in the shop this weekend with the car. Was able to borrow a smoke machine to hunt for some vacuum leaks and found that the vacuum line from the Ignition module had come off, I'm assuming this would have some consequences! Also, found leaks on both banks near the throttle plate springs on the throttle bodies. I see from the parts manual that there is a bushing in there, is this a common place to spring a small vacuum leak? It's not horrible on the 1-6 side but pretty significant on the 7-12 side
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