Super Slow Auto - 16-17 seconds to get to 60mph

Troubleshooting
1

Long post: TLRD: Car is slow, don’t know what’s wrong :frowning:

Hello everybody, having issues with my car…

I have a '95 Spyder N/A DOHC SL AUT FWD with roughly 60000km on the clock (geniun low mileage)

It is so slow, full power foot down takes around 16 to 17 seconds to 60mph (100kmph)

Car is a left hand drive, in Norway.

I am not in limp mode as i have all 3 gears plus overdrive. Foot hard down from stand still takes me to around 80kmph in roughly 10 seconds before it shifts to 2nd @ 6500 rpm. Seconds gears takes me to around 100kmph just before it shifts @ 6500 rpm for a total of around 16-17 seconds. In second gear it seems to ‘slow/bog’ for a split second around the 4000 rpm mark (this does NOT happen in 1st).

I have changed the HT leads / Spark plugs / PTU, and checked all the wiring to and from the ECU… it all looks and multi-meter pings correctly. Voltage values where applicable (according to workshop manual) seems to match of be within the specified values.

Car is a Cali version with 4 O2 sensors, but no matter what i do with these, plugged in, unplugged, before the cats, after the cats, without cats (using straight pipe) and any other possible combination seems to have no effect of the performance.

Fuel pressure has been checked and the original regulator replace with an adjustable one, currently at 2.8 bar, but tried plus 1 and minus 1 variations and all remains the same. Pressure holds at that value after the car has been off, at least for 3 to 4 minutes, maybe longer.

One thing to note, COLD - the car starts in an instant… WARM - it can take a few/several turns of the engine and a right foot to get it started…

Idle’s fine in all conditions… also in Neutral or Park it Revs up happliy

Now i know it is not a VR4 but it is about 2 times slower than what it should be (dont need to get into any arguments about this, I know it is old now and will have surely lost some power but non the less - its tpoo slow - something is wrong)

Now i got the car like this, after it was imported into Sweden and worked on to be the best 3000GT in the country, by adding a supercharger and making it fast as f@$K… the guy/garage who did this never got it working as they wanted it to be so they put it all back… i have no additional info on what they did or what they didn’t when putting it back to standard… all i know is that it has been slow since then and now im trying to find out where to start…

I bought the OBD1/MUT scanner tool from BlackStealth (3SX) and have no errors nor anything that looks our of the ordinary… but i also must admit that i have not checked deep into this as i have little knowledge about what to look for.

So, please (if you can) have a think and help me troubleshoot or eliminate things one by one so i can hopefully get my car running as it should. I don’t need no tire burning monster as it was not built to do that, but right now it is dangerous trying to pull out of junctions as i have no acceleration to do so…

Thanks in advance for any comments or help on this matter

Cheers

Ben

1 Like
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Interesting- is it possible the car isn’t reading engine temperature correctly. That is with a warm engine the ECU should adjust the fuel:air mix accordingly. If the temp sensor or ECU is wrong then it could over fuel - kind of like starting an old car with the choke out when warm - a hard start etc…

This could also explain why it bogs down but this could be many things.

3 Likes
3

Im gonna throw it out there maybe clutch slipping!

1 Like
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Engine Temp Sensor: - Yeah could be, will check it out, not sure if that is related to the performance, but you never know.

5

Clutch Slipping: Would that not slip intermittently? It seems smooth whilst increasing speeds and revs.

Here is a link to a video of my foot flat down 0-100 from a standing start

Super Slow 0-100 3000GT

Cheers

Ben

6

It’s an automatic. All SL Spyders were auto.

7

I had the exact same problem with my 93 GTO N/A. before I started to strip her down to fully rebuild. No acceleration and very slowly increasing speed even though my foot was on the floor.
I was advised on another forum that it may be the fuel pump. Subsequently while I was reconditioning various parts in the engine bay, I came across the Engine Temp Sensor and it was in a really bad way so i’ve bought a new one. While I have the tank out i’ll be replacing the pump as well just to be sure.
Hopefully that will sort the problem, But the pump may be worth thinking about. I’m by far no expert on this and rely on other people with more knowledge on forums such as these for help. Best of luck, do come back and let us know if you resolve the problem.

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Interesting, you say you had that that problem. Did you find out what it was or due to the strip-down and temp sensor / fuel pump you think it was/is that?

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Unfortunately I won’t know if the problem has been resolved until I put the car back together which will be God knows when :smile:

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I’m dealing with a similar problem in my 92 SL. I believe its due to a faulty VIC (variable induction control) motor. I’m also having a rough time finding a replacement or work around.

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ha ha sounds good, i’ll race you to the fix… see who has a faster 0-60 (100) first :slight_smile:
Good luck and thanks

Ben

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Hi, yeah i tried my VIC, mother is fine on mine but the plastic toothed cog is eaten up a little but i manage to hold it in position both open and closed (short and long) and tested both… its the same either way :frowning:

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Hi that sounds good and the rev counter goes up steadily with the engine sound which is good,have you tried an external gps like a phone to see if the speed matches on both ?
Maybe the speedo is reading low!
Dont sound like there is no power

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Would you be able to craft a new plastic cog using a 3d printer?

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might be out a little, but its dangerously slow, even pulling out of junctions is a challenge. So i can guarantee that it is not the speedo causing this. But thanks anyway.

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yeah, would be able to, but that is not the problem at this time i dont think. Cheers