 Starts out smooth, then what the buck? |
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| gunny |
 Dec 20 2013, 11:40 AM
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#21
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Member  Group: Members Posts: 205 Joined: 17-October 12 From: Madison Al Member No.: 15,051 Region Association: South East States  |
If the issue is RPM sensitive and not throttle position sensitive (like mine was) then it's not the TPS, my experance.
When you have the bogging/bucking at an RPM can you pump the throttle to get thru that RPM range? When you get above the RPM range does the car run fine? if so it's because you are very lean at that RPM. What year is your car ECU and MPS from? |
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| Jesco Reient |
Dec 20 2013, 04:22 PM
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#22
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
Today has been a research and reading day, letting the car sit for today and maybe Saturday, I also have a small block Ford to tear down this week that is getting ignored as the little German car has yelled at me to work on it. LOL
Thanks everybody for the continued input. |
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| Jesco Reient |
Dec 20 2013, 04:23 PM
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#23
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
QUOTE(gunny @ Dec 20 2013, 09:40 AM)  If the issue is RPM sensitive and not throttle position sensitive (like mine was) then it's not the TPS, my experance. When you have the bogging/bucking at an RPM can you pump the throttle to get thru that RPM range? When you get above the RPM range does the car run fine? if so it's because you are very lean at that RPM. What year is your car ECU and MPS from? 1973 2.0 D-Jet parts |
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| Jesco Reient |
Jan 22 2014, 06:59 PM
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#24
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
QUOTE(rhodyguy @ Dec 20 2013, 09:22 AM) have you calibrated the tps using a proper plug, jumper wires, and your multlmeter? Hey I'm back, So The Ford motor is disassembled and I'm back in the shop with the 914, As suggested I tried running the head temp sensor to ground to see if that changed anything, not really So it's hooked back up now. Next I'm adjusting the TPS again with the multi-meter. Next after that I'm checking the Manifold Pressure Sensor Diaphragm. It feels like it's closer to carburetors everyday. Argghhh |
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| Java2570 |
Jan 23 2014, 07:54 AM
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#25
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Senior Member Group: Members Posts: 649 Joined: 7-May 11 From: Fishers, IN Member No.: 13,035 Region Association: Upper MidWest |
I've seen a lot of other threads with folks using either Raby's 9550 or the Web 73 cams
needing to spend time tuning to get their AF mix correct. If you are running 1973 D Jet parts, you will likely at least need that 270 ohm resistor pack but I'm thinking an AF gauge would be the best bet. Even on my completely stock 2.0L with working MPS the engine tends toward the lean side. Don't give up on D Jet please! Jon |
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| mepstein |
Jan 23 2014, 09:09 AM
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#26
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914-6 GT in waiting Group: Members Posts: 19,326 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region 
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I had bucking sometimes and a perfect running engine other times. I changed the coil on mine and the bucking went away. I had tried all the other suggestions. Just a thought.
Once you get it fixed you will be glad you did not switch to carbs. |
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| Jesco Reient |
Jan 23 2014, 09:37 AM
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#27
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
QUOTE(mepstein @ Jan 23 2014, 07:09 AM) I had bucking sometimes and a perfect running engine other times. I changed the coil on mine and the bucking went away. I had tried all the other suggestions. Just a thought. Once you get it fixed you will be glad you did not switch to carbs. The coil has been nagging at my mind since that is the only part NOT replaced during the rebuild, I just have not gone there yet. The TPS is set again by the ohm-meter method, and the resistance readings on the MPS were right on the numbers. |
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| rmital |
Jan 23 2014, 11:28 AM
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#28
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Northeast optimist Group: Members Posts: 1,947 Joined: 12-December 05 From: Park Ridge, NJ Member No.: 5,268 |
QUOTE(Jesco Reient @ Jan 22 2014, 07:59 PM) ............As suggested I tried running the head temp sensor to ground to see if that changed anything, not really So it's hooked back up now. ............ just to be perfectly clear....you are NOT running the head temp sensor to ground. you would run a wire from the pigtail connection from the harness that connects to the head sensor to ground (negative on the battery) your taking the CHT out of the equation. |
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| r_towle |
Jan 23 2014, 01:37 PM
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#29
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Custom Member Group: Members Posts: 24,597 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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QUOTE(Jesco Reient @ Jan 23 2014, 10:37 AM) QUOTE(mepstein @ Jan 23 2014, 07:09 AM) I had bucking sometimes and a perfect running engine other times. I changed the coil on mine and the bucking went away. I had tried all the other suggestions. Just a thought. Once you get it fixed you will be glad you did not switch to carbs. The coil has been nagging at my mind since that is the only part NOT replaced during the rebuild, I just have not gone there yet. The TPS is set again by the ohm-meter method, and the resistance readings on the MPS were right on the numbers. Have you removed and cleaned the advance plates inside the distributor? |
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| Jesco Reient |
Jan 23 2014, 02:44 PM
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#30
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
QUOTE(rmital @ Jan 23 2014, 09:28 AM) QUOTE(Jesco Reient @ Jan 22 2014, 07:59 PM) ............As suggested I tried running the head temp sensor to ground to see if that changed anything, not really So it's hooked back up now. ............ just to be perfectly clear....you are NOT running the head temp sensor to ground. you would run a wire from the pigtail connection from the harness that connects to the head sensor to ground (negative on the battery) your taking the CHT out of the equation. Yes, I was unclear, I ran the head temp sensor pigtail of the injection harness to the negative terminal of the battery. |
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| Jesco Reient |
Jan 23 2014, 07:55 PM
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#31
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Member Group: Members Posts: 135 Joined: 18-July 12 From: Western Washington Member No.: 14,690 Region Association: Pacific Northwest |
OK, todays test drive revealed a nice smooth pull with no bucking up to 5500 RPM, then I shifted and feeling good about everything started to head out for a drive. not long after it sounded starved for fuel and shut down. So I headed back to the shop, and as I got close to the shop same thing. Back at the shop I held the RPM at aout 2500 RPM and within about three minutes same thing just sitting still.
So I'm replacing the fuel filter first thing tomorrow, then I'll hook up the pressure gauge with a long hose and see what happens when I go for a drive. But for now the bucking has left the building. Looks like the TPS was the major culprit. Thank You to all that helped. |
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