89 TR Hard to start

This is a question for Steve
First a little history. I have all new Tyco Relays (all but the K relay). I checked that both coils are working. I checked that fuel is being supplied by the fuel pumps when you turn the engine over at first. The engine tries to run but stops after a few seconds. I performed your test on the “Y” connector. Test #1 showed +12v on the two (white/blue) wires. Test #2 shows the +12v on the (beige & beige/black) during starting but drops off after a few seconds. The engine tries to run but stops. It appears that it runs out of fuel because the power to the pumps is cut off. There is a click that I hear as the power to the pumps is turned off. Does this sound like the tachometric relay (Bosh # 0280230006) if so is there a way to jump the relay to verify that it’s the problem? Can you jump the T-30 to the T-87 pin to check the relay? I have the following> T-15 >12v key on, T-30>12v from battery, T-31>ground, T-50>12v when starting. If I do need the relay where is the place to get it? Thanks in advance for your help in the problem.

 

Your description, and test results, do seem to indicate that the tachometric relay is closing properly during starter motor cranking, but (improperly) opening (and opening the fuel pump relays) when you release the key to the run position.

Yes, adding a jumper wire to directly connect the female terminal 30 to the female terminal 87 in the tachometric relay's socket (after unplugging the tachometric relay) will simulate a closed tachometric relay (and, if the engine runs well, and you have spark on both banks, that would indicate that you need a new one since you've already verified all of the other required input signals are present).

I haven't found an online source that has that particular Bosch PN available (but I haven't looked lately), so have no better recommendation than www.allferrariparts.com.

 

If you do find an on-line source please post in the TR Cross Reference thread!

CC

 

Steve, I used a paper clip and jumped 30 & 87 you could here the pumps running. I cranked the engine it fired right up and ran perfect. Looks like it's the tach relay. I'll try and find one and let you know. Thanks.

 

Sounds most likely. The only input signal that you didn't mention confirming was the signal on terminal 1 from the 7/12 coil terminal 1. If there was a break in the wiring connection between terminal 1 at the 7/12 coil and terminal 1 at the tachometric relay, that would cause the tachometric relay to open when the key was in the "run" position (even though the 7/12 bank had spark). Unfortunately, I've never made this measurement myself, nor seen a "typical" AC voltage value given in the test documentation for this measurement, but my guess would be that an AC voltage measurement between terminal 1 and terminal 31 (ground) at the tachometric relay socket when the engine is running would be some non-zero AC voltage value (i.e., 0 VAC would be a "bad" result). I'd put the probabilities at 99.99% your tachometric relay is bad and 0.01% that you have a wiring problem, but I just wanted to mention this it since the $ for a new tachometric relay aren't small.
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Just wanted to say that this thread was invaluable to me diagnosing a no-start with my TR. I want to thank all those that have contributed, especially Steve Magnusson!

With these posts I was able to diagnose my problem and pinpointed it to the Protection relay. Jumped the relay as described, car started right up. Tested the relay by applying 12v, it would not close. As you know you can’t measure coil resistance due to the 680 ohm resistor, so we took it apart, unsoldered the resistor and confirmed a bad (open) coil. Installed a new relay, it is running again.

If it weren’t for the expert advice on this forum and the willingness to help, I would have given up. What made the problem especially confusing was that 2 weeks ago I had a similar issue but totally different root cause (bad connection at violet wire coming out of the tachometric relay).

I think it was Archimedes who said “give me a voltmeter, perseverance and F-Chat and I can move the world!

 

Found some comps:


Hella 008189122
Hella 4RP 008 189-111. Alfa Romeo,Audi.VW
Citroen 92521569
Hella. 008189121
Huco. 132041
Peugeot 9100040980

www.bestpartstore.co.uk/936666. Supposedly in stock.

 

continued...
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Vince -- did you mis-type here? Did you replace the Protection relay or the Tachometric relay?

 

This is important. Steve needs to maintain his 100% strike rate

 

Steve,
I replaced the protection relay. What made all this so complicated was that 3 weeks ago I had a no-start but totally different symptom and cause. The first time was the symptom that it would fire when cranking but not when I let off the starter. That was the violet wire. During that search we did discuss availability of tachometric relays and you pointed me to the one on eBay (which I did btw end up buying as it was brand-new still in the Bosch box)

The second time I knew the tachometric relay (and violet wire) was OK because I could hear the fuel pumps running and also I had put pressure gages on both FDs and had 41 PSI. The symptom this time was that it would start but only run two seconds.

Can't help but wonder that the second problem happened within 3 weeks of the first. Maybe the intermittent violet connection cycled the protection relay too much and fatigued it (I think coils are subject to fatigue like mechanical parts).

 

Thanks for the clarification Vince (about both which component was replaced and the corresponding change in symptom). More F models use the Protection relay than the Tachometric relay so it's natural that we'd get more posts about Protection relay trouble, but I can't recall any prior report of someone needing to replace the Tachometric relay so I'll leave that in my mind as a very rare thing (unfortunately, the original poster of this thread never came back to give a final report...).

 

It is always nice to have Steve on the sideline. Thank you Steve!

 

as I see it this tachometric relais is only for the fuel pumps that when the engine is not running the pums also stop.
and during starting the engine and running this relais tells the fuelpump relais to work. right?
I ask only because I just put this all out of my car. this safety the 2 new ECU will do this.

 

Correct -- the Tachometric relay closes the fuel pump relays to run the fuel pumps only:

1) during starter motor cranking (key Pos III), or

2) if the key is "on" (Pos II) and if the 7-12 coil primary winding is firing.

 

ok thank you steve.

I was a little confused because of the name "tachometric relais". in german a tacho is a speedometer, and the translator tell then "tachometrisches relais", but this is not german
so it is more a safety relais in my eyes.

I only wanted to make sure that I don´t need this anymore.


I must repeat: this is a very special forum with a lot of knowledge

 

Yes, even in English "tachometric" isn't a great description -- it should really be called something like an "(Ignition) Pulse Detecting Relay" or "Safety Relay" as you suggest.

 

I must still have one (or more) unreliable connections because once again it did not start. This time the symptom was different than in the past in that did not fire at all. Rereading the threads (hope this summary is correct):
1. if it is in the the tachometric relay or circuit (violet wire) it will fire when the starter is engaged but dies when you let off. This time it did not fire when on the starter. I measured ~10.5 volts at the violet wire.

2. if it is in the protection relay or circuit, (usually) it will run for a couple of seconds (while on the cold-start injectors), then die. This time it did not fire at all

The fuel pumps are supposed to come on for ~ 2 seconds when you first turn the ignition on, and this time they did not come on. Puzzling is that I measure 40 - 42 psi at both fuel-distributor heads.

As the protection relay is new and the violet wire had voltage, I looked for spark. I have an old Tektronix scope, so I hooked that up the next day. While looking for a good ground I noticed the left-bank ground wire (6 mm bolt) was not as tight as I would have liked, so I removed it, cleaned the terminals, re-installed. Fired right up.

But was this because it sat a day, or due to the ground? I know a bad ground will disable the ignition and the tachometric relay would not have sensed left-bank ignition, but I would have thought that the car would have fired when on the starter as the ignition-sensing is bypassed when cranking.

 

That's OK (especially if the starter motor is cranking) -- but if the fuel pumps were not running that would indicate a problem on the fuse-relay panel (but your later pressure measurement seems OK -- like the fuel pumps did run).

This is true, but, if the ambient is above about 78 deg F, the cold start injectors will not fire. Also, after the first cranking attempt, even if the ambient temp is colder, the Thermo-time switch will have been self-heated so the cold start injectors may not fire on immediate subsequent attempts.

No, the TR fuel pumps do not run for ~2 secs when the key is just turned "on". Since you measured the correct residual fuel pressure (a little less than ~3 bar), the fuel pumps did run recently (if the car had sat overnight unused).

Yes, the ignition-sensing isn't used during starter motor cranking, but cranking-sensing is used -- so that still requires a working tachometric relay. However since you report measuring the 10.5V on the violet wire that seems OK.

I know that I've said nothing to help you, but if you have another problem, and can make/report similar measurements, I'd be glad to review/comment.

 

Steve,
Thanks as always for the quick and expert response. You have indeed said some things to help me:
Ambient was just over 78F, which is why the cold-start injectors did not fire
You corrected me about the fuel pumps coming on for ~ 2 seconds when the key is turned on. When the car is acting properly I always hear what I thought were the fuel pumps for ~ 2 seconds. If that sound is absent, the car does not start.

An embarassing mistake.

So if you can tell me what is being energized during that initial key-on, then I can trace that circuit for missing voltage.

 

Can't help here -- the only thing that I know of that might make a slight whirring sound when first turning the key "on" is the little air blower fan in the cabin air temp assembly sensor in the left side of the dash -- nothing related to the engine operation.

 

Steve,
I traced the problem to the blue wire at the bottom of the W connector. When I wiggle the wire, the car dies. I can't really differentiate if it is the blue wire at the very bottom of W or the one above it because I can't touch one without brushing up against the other.

I will of course replace those contacts, but I was wondering if I should solder a jumper while I have the connector apart, in order to bypass any problems in the fuse box.
Also I am wondering if my wires are correct. According to the WSM the bottom blue should be a double wire (one of which leads to the tachometric relay, the other to terminal 15 of the ignition switch) and the second to bottom one is a single wire also going to terminal 15. Mine is different though, as the bottom is a single wire, the second one is two wires and they are blue with black stripes. Don't know if that makes a difference.

So does a jumper from the bottom wire to the second wire even make sense as they are anyway joined at the ignition switch? Or where should the jumper go?
I did already install jumpers within the fuse box for the high-current circuits, but it was not a complete rewire (which I most probably should do).

By the way, if I wiggle the wire with the ignition switch on but without the car running, I can turn that whirring noise that I mentioned in my earlier post on and off. Probably the absence of the noise (related to when the car won't start) is merely a secondary symptom (i assume the real cause of the no-start is a bad connection to the tachometric relay), but I did record the noise.
View attachment tr_blue_wire.wav

 

Vince -- You shouldn't be using the schematics in the TR WSM (because they only correspond to an early euro TR). What you need is Fig 2 and Fig 3 in the 509/88 US TR wiring diagram book (you can download a copy of 509/88 from All Ferraris). The wire colors in Fig 2 and Fig 3 of 509/88 match what you report:

bottom position in w connector = one large A (light blue) wire from ignition switch terminal 15 -- exits the fuse relay panel thru two yellow wires (in separate positions) in the y connector to run the LH and RH coils respectively.

2nd from bottom position in w connector = two AN (light blue-black) wires -- one large one from ignition switch terminal 15 -- exits the fuse-relay panel thru one GN (yellow-black) wire in the y connector to run the MicroPlex ignition ECU; and one smaller AN wire that goes to the tachometric relay.

You could add a "jumper" from the large AN wire to the GN wire in the y connector, but the large AN wire needs to stay connected to the fuse-relay panel because it is also used to close relay S (and it needs to stay connected to the smaller AN wire going to the tachometric relay).

Likewise, you could add a jumper wire to connect from the large A wire to two G wires in the y connector. This A wire only connects to those G wires so it doesn't matter if the A wire stays connected to the fuse-relay panel, but I'd recommend that you leave everything "stock" (after repairing ), and then just add these jumpers (if desired) to act in parallel with the stock traces on the fuse-relay panel.

 

Steve,
Thanks very much (again) for the prompt and expert reply! I will download the correct manual and add the jumpers you suggested.

 

Steve,
Adding those jumpers did the trick. Car runs fine, I even wiggled the wires on the W connecter to be 100% sure (when I did this before the car would die), it stayed running.

Thanks again.