So I have a 91 DOHC ZC in my DX Hatch... I had a new distributor and plugs put on about 6 months ago but this problem existed before all that. Also put on a new IACV and Distributor around that time to solve a jumpy idle issue. The car has no aftermarket additions.

I am running OBD0

The car runs great when it is cold (unless it is really cold then I have to hold WOT and it barely chugs along) but once it warms up it has a hesitation or a sputter from a dead stop, until it reaches around 2500 rpm...

The car runs great at idle.

Just trying to figure out what this could be, I dont even know where to start.

 

same thing happed to my frieds car it was tha ecu... if not check all ur vacum lines an hoses

 

also might try an adjust tha tps

 

Thankx for the reply.. I am doing a full tune up on the car in the next week... But thought I would check here to see if I have planned correctly...

I will be doing: Plugs, wires, Fuel filter. cap, rotor, and oil change..... hopefully this is all it needs.. Will also be putting header, 02 sensor, and catback on it... hopefully this resolves issues..... I will do one at a time and report here for progress on hesitation issue.. hopefully it will answer some questions to this issue...

possibly also ordering a new MAP sensor just in case,... Any other ideas would be helpful...

*****UPDATE****

So I have ordered all my parts for the tune up, and I am just waiting for them to be delivered. Something interesting though... The hesitation was getting so bad and annoying that I couldnt take it anymore, so I went and got some Octane booster, dry gas, and filled my tank. After a few days no improvement.

I took some advice from another post on Honda-Tech (and thezcr) and I bought some Seafoam... Added about 3/4 pint in fuel tank and the remaining into the oil, and after a day or so, the majority of the hesitation is gone... Still has a little but it goes away a lot faster, not to mention the car seems to run a lot smoother...

Unfortunately it still wants to misbehave badly when it is really cold, like tonight. Thankfully it straightens right up once it warms up.

Any info on that would be greatly appreciated...

Thanks in advance...

 

i had a simalar problem when i put in a y7 in my 91 dx and i did pretty much what you did and nothing changed so i took to get looked at and my bousch 02 sensor was ****n up so put in a stock sensor in and now runs awesome

 

Have checked the ECU for codes?? What are they?

 

I am not getting any codes.

 

so no check engine light odd and it runs like **** you already did the tune up or are you still waiting

 

I was not getting a check engine light or any error codes at the ECU...

At the time of your post I had not done the Tuneup; however, today I Changed the plugs and wires. The hesitation seems to completely gone. I will monitor for the next few days and post here if the issue returns.

Something that struck me as odd is that on each one of the plugs the the tips were real lose, almost to the point of falling off (the top or terminal of the plug not the electrodes). They were Denso Q20PR-U 11. I put in the NGK Performance plugs (not iridium or platinum) and I used the NGK HE48 wires. Thing runs better now than when I bought it.

The electrode end or bottom of the plug was black and pretty thick with soot and the ground electrode had a white buildup, or haze. The plugs didn't smell of fuel and I am not loosing any coolant. I do go through between 1/2 and one quart of Oil every 2-3 weeks but I don't think that is excessive for the age of the engine, and I don't have any smoke from exhaust (think it is just a little leaky).

Well Thank you for reading and helping... If you have any other suggestions for the cold start thing that would be cool. I plan on changing the Header, o2 sensor, and the exhaust in the next week so I will post more then (unless I have any issues of course).